I'm using the WCF4.0 template -REST. I'm trying to make a method that uploads a file using a stream.
The problem always occur at
Stream serverStream = request.GetRequestStream();
Class for streaming:
namespace LogicClass
{
public class StreamClass : IStreamClass
{
public bool UploadFile(string filename, Stream fileStream)
{
try
{
FileStream fileToupload = new FileStream(filename, FileMode.Create);
byte[] bytearray = new byte[10000];
int bytesRead, totalBytesRead = 0;
do
{
bytesRead = fileStream.Read(bytearray, 0, bytearray.Length);
totalBytesRead += bytesRead;
} while (bytesRead > 0);
fileToupload.Write(bytearray, 0, bytearray.Length);
fileToupload.Close();
fileToupload.Dispose();
}
catch (Exception ex) { throw new Exception(ex.Message); }
return true;
}
}
}
REST project:
[WebInvoke(UriTemplate = "AddStream/{filename}", Method = "POST", BodyStyle = WebMessageBodyStyle.Bare)]
public bool AddStream(string filename, System.IO.Stream fileStream)
{
LogicClass.FileComponent rest = new LogicClass.FileComponent();
return rest.AddStream(filename, fileStream);
}
Windows Form project: for testing
private void button24_Click(object sender, EventArgs e)
{
byte[] fileStream;
using (FileStream fs = new FileStream("E:\\stream.txt", FileMode.Open, FileAccess.Read, FileShare.Read))
{
fileStream = new byte[fs.Length];
fs.Read(fileStream, 0, (int)fs.Length);
fs.Close();
fs.Dispose();
}
string baseAddress = "http://localhost:3446/File/AddStream/stream.txt";
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(baseAddress);
request.Method = "POST";
request.ContentType = "text/plain";
Stream serverStream = request.GetRequestStream();
serverStream.Write(fileStream, 0, fileStream.Length);
serverStream.Close();
using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
{
int statusCode = (int)response.StatusCode;
StreamReader reader = new StreamReader(response.GetResponseStream());
}
}
I've turned off the firewall and my Internet connection, but the error still exists. Is there a better way of testing the uploading method?
Stack trace:
at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Int32 timeout, Exception& exception)
"Actively refused it" means that the host sent a reset instead of an ack when you tried to connect. It is therefore not a problem in your code. Either there is a firewall blocking the connection or the process that is hosting the service is not listening on that port. This may be because it is not running at all or because it is listening on a different port.
Once you start the process hosting your service, try netstat -anb (requires admin privileges) to verify that it is running and listening on the expected port.
update: On Linux you may need to do netstat -anp instead.
You don't have to restart the PC. Restart IIS instead.
Run -> 'cmd'(as admin) and type "iisreset"
You must set up your system proxy
You have to go through this path
controlpanel>>internet option>>connnection>>LAN settings>>
proxy
no tik:use proxy server
I got a similar error message like TCP error code 10061: No connection could be made because the target machine actively refused it in my current project. I find this 10061 error code cannot distinguish the case that the service endpoint is not started and the case that it is blocked by the firewall. Often, the firewall can be switched off, but the problem is still there.
You can test your code in the below two ways.
Insert code to get time A that service is started and time B that client sends the request to the server. If B is earlier than A, it can cause this problem.
Change your server port to another port that is also available in the system. You will find the same error code reported.
Above is my fix. It works on my machine. I hope it helps!
Check if any other program is using that port.
If an instance of the same program is still active, kill that process.
I had a similar issue. In my case the service would work fine on the developer machine but fail when on a QA machine. It turned out that on the QA machine the application wasn't being run as an administrator and didn't have permission to register the endpoint:
HTTP could not register URL http://+:12345/Foo.svc/]. Your process does
not have access rights to this namespace (see
http://go.microsoft.com/fwlink/?LinkId=70353 for details).
Refer here for how to get it working without being an admin user: https://stackoverflow.com/a/885765/38258
If you use WCF storm, can you even log-in to the WCF service endpoint? If not, and you are hosting it in a Windows service, you probably forgot to register that namespace. It's not very well advertised that this step is required, and it is actually annoying to do.
I use this tool to do this; it automates all those cumbersome steps.
Check whether the port number in file Web.config of your webpage is the same as the one that is hosted on IIS.
I had the same problem on my web server "No connection could be made because the target machine actively refused it 161.x.x.235:5672". I asked the Admin to open the port 5672 on the web server, then it worked fine.
I had a similar problem
rejecting localhost and 127.0.0.1.
cmd(admin) netstat -anb found the port running on 169.254.80.80 (dont know were that ip came from because my network ip was 10.0.0.5.
after putting in this IP it worked.
This Gives correct IP:
IPAddress ipAddress = ipHostInfo.AddressList[0];
Console.WriteLine(ipAddress.ToString());
I also faced problem in .Net Remoting Service in C#.
I got it solved in 3 steps:
Change Port of Protocol in all the files whereever it is being used.
Run your Host Server Program and make it active.
Now run your client program.
I could not restart IIexpress. This is the solution that worked for me
Cleaned the build
Rebuild
With this error I was able to trace it, thanks to #Yaur, you need to basically check the service (WCF) if it's running and also check the outbound and inbound TCP properties on your advance firewall settings.
With similar pattern, my rest client is calling the service API, the service called successfully when debugging, but not working on the published code. Error was: Unable to connect to the remote server.
Inner Exception: System.Net.Sockets.SocketException (0x80004005): No connection could be made because the target machine actively refused it serviceIP:443 at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress) at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Exception& exception)
Resolution: Set the proxy in Web config.
<system.net>
<defaultProxy useDefaultCredentials="true">
<proxy proxyaddress="http://proxy_ip:portno/" usesystemdefault="True"/>
</defaultProxy>
</system.net>
I had a similar issue. In my case VPN proxy app such as Psiphon ، changed the proxy setup in windows so follow this :
in Windows 10, search change proxy settings and turn of use proxy server in the manual proxy
Make Sure all services used by your application are on, which are using host and port to utilize them . For e.g, as in my case, This error can come, If your application is utilizing a Redis server and it is not being able to connect to it on given port and host, thus producing this error .
For my case, I had an Angular SLA project template with ASP.NET Core.
I was trying to run the IIS Express from the Visual Studio WebUI solution, triggering the "Actively refused it" error.
The problem, in this case, wasn't connected with the Firewall blocking the connection.
It turned out that I had to run the Angular server independently of the Kestrel run because the Server was expecting the UI to run on a specific port but wasn't actually.
For more information, check the official Microsoft documentation.
I had similar problem. In launchSettings, my IIS Express was configured on one port, and there was another launch profile that started on another ApplicationUrl with another port.
Starting the web app up with the IIS Express profile led me to have the error.
I am using the Apache ActiveMQ Artemis AMQP message broker. I started getting the "No connection could be made because the target machine actively refused it" exception when trying to send and receive messages with the broker after a reboot. On a computer where the same type of broker still worked, netstat -anb showed that the broker was listening on the expected port 5672. On the computer with the error, the broker was not listening. On the computer with the error, starting the broker resulted in the following warning's appearing in Microsoft Event Viewer's "Windows Logs > System":
The system failed to register host (A or AAAA) resource records for network adapter
with settings:
Adapter Name : {286EE2DA-3D81-41AE-VE5G-5D761FD3925E}
Host Name : mypc
Primary Domain Suffix : myco.com
DNS server list :
55.77.168.1, 74.86.130.1
Sent update to server : 186.952.335.157:45
IP Address(es) :
182.269.1.437
Either the DNS server does not support the DNS dynamic update protocol or the authoritative zone for the specified DNS domain name does not accept dynamic updates.
To register the DNS host (A or AAAA) resource records using the specific DNS domain name and IP addresses for this adapter, contact your DNS server or network systems administrator.
I was able to use the broker without error after I ran the following in a cmd.exe with administrative privileges, rebooted, and waited about fifteen minutes:
ipconfig /flushdns
ipconfig /renew
ipconfig /registerdns
Sometimes I get the following error while I was doing HttpWebRequest to a WebService. I copied my code below too.
System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it 127.0.0.1:80
at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.Sockets.Socket.InternalConnect(EndPoint remoteEP)
at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Int32 timeout, Exception& exception)
--- End of inner exception stack trace ---
at System.Net.HttpWebRequest.GetRequestStream()
ServicePointManager.CertificatePolicy = new TrustAllCertificatePolicy();
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.PreAuthenticate = true;
request.Credentials = networkCredential(sla);
request.Method = WebRequestMethods.Http.Post;
request.ContentType = "application/x-www-form-urlencoded";
request.Timeout = v_Timeout * 1000;
if (url.IndexOf("asmx") > 0 && parStartIndex > 0)
{
AppHelper.Logger.Append("#############" + sla.ServiceName);
using (StreamWriter reqWriter = new StreamWriter(request.GetRequestStream()))
{
while (true)
{
int index01 = parList.Length;
int index02 = parList.IndexOf("=");
if (parList.IndexOf("&") > 0)
index01 = parList.IndexOf("&");
string parName = parList.Substring(0, index02);
string parValue = parList.Substring(index02 + 1, index01 - index02 - 1);
reqWriter.Write("{0}={1}", HttpUtility.UrlEncode(parName), HttpUtility.UrlEncode(parValue));
if (index01 == parList.Length)
break;
reqWriter.Write("&");
parList = parList.Substring(index01 + 1);
}
}
}
else
{
request.ContentLength = 0;
}
response = (HttpWebResponse)request.GetResponse();
If this happens always, it literally means that the machine exists but that it has no services listening on the specified port, or there is a firewall stopping you.
If it happens occasionally - you used the word "sometimes" - and retrying succeeds, it is likely because the server has a full 'backlog'.
When you are waiting to be accepted on a listening socket, you are placed in a backlog. This backlog is finite and quite short - values of 1, 2 or 3 are not unusual - and so the OS might be unable to queue your request for the 'accept' to consume.
The backlog is a parameter on the listen function - all languages and platforms have basically the same API in this regard, even the C# one. This parameter is often configurable if you control the server, and is likely read from some settings file or the registry. Investigate how to configure your server.
If you wrote the server, you might have heavy processing in the accept of your socket, and this can be better moved to a separate worker-thread so your accept is always ready to receive connections. There are various architecture choices you can explore that mitigate queuing up clients and processing them sequentially.
Regardless of whether you can increase the server backlog, you do need retry logic in your client code to cope with this issue - as even with a long backlog the server might be receiving lots of other requests on that port at that time.
There is a rare possibility where a NAT router would give this error should its ports for mappings be exhausted. I think we can discard this possibility as too much of a long shot though, since the router has 64K simultaneous connections to the same destination address/port before exhaustion.
The most probable reason is a Firewall.
This article contains a set of reasons, which may be useful to you.
From the article, possible reasons could be:
FTP server settings
Software/Personal Firewall Settings
Multiple Software/Personal Firewalls
Anti-virus Software
LSP Layer
Router Firmware
Computer Turned Off
Computer Not Plugged In
Fiddler
I had the same. It was because the port-number of the web service was changing unexpectedly.
This problem usually happens when you have more than one copy of the project
My project was calling the Web service with a specific port number which I assigned in the Web.Config file of my main project file. As the port number changed unexpectedly, the browser was unable to find the Web service and throwing that error.
I solved this by following the below steps: (Visual Studio 2010)
Go to Properties of the Web service project --> click on Web tab --> In Servers section --> Check Specific port
and then assign the standard port number by which your main project is calling the web service.
I hope this will solve the problem.
Cheers :)
I think, you need to check your proxy settings in "internet options". If you are using proxy/'hide ip' applications, this problem may be occurs.
I had the same problem. The problem is that I didn't start the selenium server. I have downloaded the selenium server and i started it. After starting the selenium server, issue gone and all worked fine.
Refer this : http://coding-issues.blogspot.in/2012/11/no-connection-could-be-made-because.html
I had the same error with my WCF service using Net TCP binding, but resolved after starting the below services in my case.
Net.Pipe.Listener.Adapter
Net.TCP.Listener.Adapter
Net.Tcp Port Sharing Service
In my case, some domains worked, while some did not. Adding a reference to my organization's proxy Url in my web.config fixed the issue.
<system.net>
<defaultProxy useDefaultCredentials="true">
<proxy proxyaddress="http://proxy.my-org.com/" usesystemdefault="True"/>
</defaultProxy>
</system.net>
When you call service which has only HTTP (ex: http://example.com) and you call HTTPS (ex: https://example.com), you get exactly this error - "No connection could be made because the target machine actively refused it"
I faced same error because when your Server and Client run on same machine the Client need server local ip address not Public ip address to communicate with server you need Public ip address only in case when Server and Client run on separate machine so use Local ip address in client program to connect with server Local ip address can be found using this method.
public static string Getlocalip()
{
try
{
IPAddress[] localIPs = Dns.GetHostAddresses(Dns.GetHostName());
return localIPs[7].ToString();
}
catch (Exception)
{
return "null";
}
}
I got this error in an application that uses AppFabric. The clue was getting a DataCacheException in the stack trace. To see if this is the issue for you, run the following PowerShell command:
#("AppFabricCachingService","RemoteRegistry") | % { get-service $_ }
If either of these two services are stopped, then you will get this error.
For me, I wanted to start the mongo in shell (irrelevant of the exact context of the question, but having the same error message before even starting the mongo in shell)
The process 'MongoDB Service' wasn't running in Services
Start cmd as Administrator and type,
net start MongoDB
Just to see MongoDB is up and running just type mongo, in cmd it will give Mongo version details and Mongo Connection URL
Well, I've received this error today on Windows 8 64-bit out of the blue, for the first time, and it turns out my my.ini had been reset, and the bin/mysqld file had been deleted, among other items in the "Program Files/MySQL/MySQL Server 5.6" folder.
To fix it, I had to run the MySQL installer again, installing only the server, and copy a recent version of the my.ini file from "ProgramData/MySQL/MySQL Server 5.6", named my_2014-03-28T15-51-20.ini in my case (don't know how or why that got copied there so recently) back into "Program Files/MySQL/MySQL Server 5.6".
The only change to the system since MySQL worked was the installation of Native Instruments' Traktor 2 and a Traktor Audio 2 sound card, which really shouldn't have caused this problem, and no one else has used the system besides me. If anyone has a clue, it would be kind of you to comment to prevent this for me and anyone else who has encountered this.
For service reference within a solution.
Restart your workstation
Rebuild your solution
Update service reference in WCFclient project
At this point, I received messsage (Windows 7) to allow system access.
Then the service reference was updated properly without errors.
I would like to share this answer I found because the cause of the problem was not the firewall or the process not listening correctly, it was the code sample provided from Microsoft that I used.
https://msdn.microsoft.com/en-us/library/system.net.sockets.socket%28v=vs.110%29.aspx
I implemented this function almost exactly as written, but what happened is I got this error:
2016-01-05 12:00:48,075 [10] ERROR - The error is: System.Net.Sockets.SocketException (0x80004005): No connection could be made because the target machine actively refused it [fe80::caa:745:a1da:e6f1%11]:4080
This code would say the socket is connected, but not under the correct IP address actually needed for proper communication. (Provided by Microsoft)
private static Socket ConnectSocket(string server, int port)
{
Socket s = null;
IPHostEntry hostEntry = null;
// Get host related information.
hostEntry = Dns.GetHostEntry(server);
// Loop through the AddressList to obtain the supported AddressFamily. This is to avoid
// an exception that occurs when the host IP Address is not compatible with the address family
// (typical in the IPv6 case).
foreach(IPAddress address in hostEntry.AddressList)
{
IPEndPoint ipe = new IPEndPoint(address, port);
Socket tempSocket =
new Socket(ipe.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
tempSocket.Connect(ipe);
if(tempSocket.Connected)
{
s = tempSocket;
break;
}
else
{
continue;
}
}
return s;
}
I re-wrote the code to just use the first valid IP it finds. I am only concerned with IPV4 using this, but it works with localhost, 127.0.0.1, and the actually IP address of you network card, where the example provided by Microsoft failed!
private Socket ConnectSocket(string server, int port)
{
Socket s = null;
try
{
// Get host related information.
IPAddress[] ips;
ips = Dns.GetHostAddresses(server);
Socket tempSocket = null;
IPEndPoint ipe = null;
ipe = new IPEndPoint((IPAddress)ips.GetValue(0), port);
tempSocket = new Socket(ipe.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
Platform.Log(LogLevel.Info, "Attempting socket connection to " + ips.GetValue(0).ToString() + " on port " + port.ToString());
tempSocket.Connect(ipe);
if (tempSocket.Connected)
{
s = tempSocket;
s.SendTimeout = Coordinate.HL7SendTimeout;
s.ReceiveTimeout = Coordinate.HL7ReceiveTimeout;
}
else
{
return null;
}
return s;
}
catch (Exception e)
{
Platform.Log(LogLevel.Error, "Error creating socket connection to " + server + " on port " + port.ToString());
Platform.Log(LogLevel.Error, "The error is: " + e.ToString());
if (g_NoOutputForThreading == false)
rtbResponse.AppendText("Error creating socket connection to " + server + " on port " + port.ToString());
return null;
}
}
This is really specific, but if you receive this error after trying to connect to a database using mongo, what worked for me was running mongod.exe before running mongo.exe and then the connection worked fine. Hope this helps someone.
One more possibility --
Make sure you're trying to open the same IP address as where you're listening. My server app was listening to the host machine's IP address using IPv6, but the client was attempting to connect on the host machine's IPv4 address.
I've received this error from referencing services located on a WCFHost from my web tier. What worked for me may not apply to everyone, but I'm leaving this answer for those whom it may. The port number for my WCFHost was randomly updated by IIS, I simply had to update the end routes to the svc references in my web config. Problem solved.
In my scenario, I have two applications:
App1
App2
Assumption: App1 should listen to App2's activities on Port 5000
Error: Starting App1 and trying to listen, to a nonexistent ghost town, produces the error
Solution: Start App2 first, then try to listen using App1
Go to your WCF project -
properties ->
->
debuggers
-> unmark the checkbox
Enable Edit and Continue
In my case this was caused by a faulty deployment where a setting in my web.config was not made.
A collegue explained that the IP address in the error message represents the localhost.
When I corrected the web.config I was then using the correct url to make the server calls and it worked.
I thought I would post this in case it might help someone.
Using WampServer 64bit on Windows 7 Home Premium 64bit I encountered this exact problem. After hours and hours of experimentation it became apparent that all that was needed was in my.ini to comment out one line. Then it worked fine.
commented out 1 line
socket=mysql
If you put your old /data/ files in the appropriate location, WampServer will accept all of them except for the /mysql/ folder which it over writes. So then I simply imported a backup of the /mysql/ user data from my prior development environment and ran FLUSH PRIVILEGES in a phpMyAdmin SQL window. Works great. Something must be wrong because things shouldn't be this easy.
I had this issue happening often. I found SQL Server Agent service was not running. Once I started the service manually, it got fixed. Double check if the service is running or not:
Run prompt, type services.msc and hit enter
Find the service name - SQL Server Agent(Instance Name)
If SQL Server Agent is not running, double-click the service to open properties window. Then click on Start button. Hope it will help someone.
I came across this error and took some time to resolve it. In my case I had https and net.tcp configured as IIS bindings on same port. Obviously you can't have two things on the same port. I used netstat -ap tcp command to check whether there is something listening on that port. There was none listening. Removing unnecessary binding (https in my case) solved my issue.
It was a silly issue on my side, I had added a defaultproxy to my web.config in order to intercept traffic in Fiddler, and then forgot to remove it!
There is a service called "SQL Server Browser" that provides SQL Server connection information to clients.
In my case, none of the existing solutions worked because this service was not running. I resumed it and everything went back to working perfectly.
I was facing this issue today. Mine was Asp.Net Core API and it uses Postgresql as the database. We have configured this database as a Docker container. So the first step I did was to check whether I am able to access the database or not. To do that I searched for PgAdmin in the start as I have configured the same. Clicking on the resulted application will redirect you to the http://127.0.0.1:23722/browser/. There you can try access your database on the left menu. For me I was getting an error as in the below image.
Enter the password and try whether you are able to access it or not. For me it was not working. As it is a Docker container, I decided to restart my Docker desktop, to do that right click on the docker icon in the task bar and click restart.
Once after restarting the Docker, I was able to login and see the Database and also the error was gone when I restart the application in Visual Studio.
Hope it helps.
it might be because of authorisation issues; that was the case for me.
If you have for example: [Authorize("WriteAccess")] or [Authorize("ReadAccess")] at the top of your controller functions, try to comment them out.
I just faced this right now...
Here on my end, I have 2 separated Visual Studio solutions (.sln)... opened each one in their own Visual Studio instance.
Solution 2 calls Solution 1 code. The problem was related to the port assigned to Solution 1. I had to change the port on solution 1 to another one and then Solution 2 started working again. So make sure you check the port assigned to your project.
Normally, connection scripts do not mention the port to use. For example:
$mysqli = mysqli_connect('127.0.0.0.1', 'user', 'password', 'database');
So, to connect with a manager that doesn't use port 3306, you have to specify the port number on the connection request:
$mysqli = mysqli_connect('127.0.0.0.1', 'user', 'password', 'database', '3307');
To check the connections on the MySQL or MariaDB database manager, use the script:
wamp(64)\www\testmysql.php
by putting 'http://localhost/testmysql.php' in the browser address bar having first modified the script according to your parameters.
I forgot to start the service so it failed because no service was listening on port.
Resolved by starting the service.
So, I am running a Ratchet (php) websocket server with multiple routes that connect do multiple Ratchet apps (MessageComponentInterfaces):
//loop
$loop = \React\EventLoop\Factory::create();
//websocket app
$app = new Ratchet\App('ws://www.websocketserver.com', 8080, '0.0.0.0', $loop);
/*
* load routes
*/
$routeOne = '/example/route';
$routeOneApp = new RouteOneApp();
$app->route($routeOne, $routeOneApp, array('*'));
$routeTwo = '/another/route';
$routeTwoApp = new AnotherApp();
$app->route($routeTwo, $routeTwoApp, array('*'));
From here I am binding a ZMQ socket, in order to be able to receive messages sent from php scripts run on the normal apache server.
// Listen for the web server to make a ZeroMQ push after an ajax request
$context = new \React\ZMQ\Context($loop);
$pull = $context->getSocket(\ZMQ::SOCKET_PULL);
$pull->bind('tcp://127.0.0.1:5050'); // Binding to 127.0.0.1 means the only client that can connect is itself
$pull->on('message', array($routeOneApp, 'onServerMessage'));
Finally, the server is started:
//run
$loop->run();
This works perfectly fine as long as i am binding only one of the ratchet apps to the ZMQ socket. However, i would like to be able to separately push messages to both of the Ratchet apps. For this purpose i thought of binding two ZMQ sockets to different routes like:
$pullOne->bind('tcp://127.0.0.1:5050' . $routeOne); // Binding to 127.0.0.1 means the only client that can connect is itself
$pullOne->on('message', array($routeOneApp, 'onServerMessage'));
and
$pullTwo->bind('tcp://127.0.0.1:5050' . $routeTwo); // Binding to 127.0.0.1 means the only client that can connect is itself
$pullTwo->on('message', array($routeTwoApp, 'onServerMessage'));
However, this leads to an error message from ZMQ when binding the second socket, saying the given address is already in use.
So the question is, is there any other way to use routes over a ZMQ socket?
Or should i use other means to distinguish between messages for the separate Ratchet apps, and if so, what would be a good solution?
I thought about binding to 2 different ports, but figured that would be a pretty ugly solution?!
In general in TCP packets are identified by the 4 tuple (sender ip, sender port, receiver ip, receiver port).
When a incoming packet reaches the network layer, it is forwarded to the appropriate application by looking at the receiver ip and port. If you use the same pair for both the apps, it will be impossible for the layer to decide whom to send it to when a connection comes in.
One solution would be to bind a single connection and the write a common handler that looks at the incoming content and then decides (I assume you have some logic) to differentiate the incoming connections to the different instances and then invokes the corresponding handler. The handler can get the connection object and can handle the connection hence forth.
If both your instances are identical and it doesn't matter who gets the request then you can just randomly forward the new connection to any of the handler.
Edit: I have tried to answer the question irrespective of the application type (Racket/ZMQ etc) because the issue you are trying to address is a fundamental one common to any network application.
For this case since you have two apps running and want to listen on the same port, you can have a common handler which can look at the request URL and forward the connection to the appropriate handler.
The request URL can be obtained using
$querystring = $conn->WebSocket->request->getQuery();
Now the clients can connect using
ws://localhost:5050/app1
and
ws://localhost:5050/app2
Your different apps can now handle these connections separately.