PHPMailer could not connect to SMTP host - php

Question

getting following error:
SMTP -> ERROR: Failed to connect to server: php_network_getaddresses: getaddrinfo failed: No such host is known. (0)
SMTP Error: Could not connect to SMTP host. There was a problem sending this mail!
This is my config file setting as I have followed this PHPMailer tutorial
// Configuration settings for My Site
// Email Settings
$site['from_name'] = 'Manish Dekavadiya'; // from email name
$site['from_email'] = 'manish#<my-domain>.com'; // from email address
// Just in case we need to relay to a different server,
// provide an option to use external mail server.
$site['smtp_mode'] = 'enabled'; // enabled or disabled
$site['smtp_host'] = "smtp.<my-domain>.com";
$site['smtp_port'] = 587;
$site['smtp_username'] = "manish#<my-domain>.com";
$site['smtp_password']="<password>";
and used mailer class and an extended class as mentioned in tutorial as following:
/*****sendmail.php****/
// Grab our config settings
require_once($_SERVER['DOCUMENT_ROOT'].'/config.php');
// Grab the FreakMailer class
//echo $_SERVER['DOCUMENT_ROOT'];
require_once($_SERVER['DOCUMENT_ROOT'].'/lib/MailClass.inc');
// instantiate the class
$mailer = new FreakMailer();
// Set the subject
$mailer->Subject = 'This is a test';
$mailer->SMTPDebug = 1;
// Body
$mailer->Body = 'This is a test of my mail system!';
// Add an address to send to.
$mailer->AddAddress('manish.dekavadiya#gmail.com', 'Manish Dekavadiya');
if(!$mailer->Send())
{
echo 'There was a problem sending this mail!';
}
else
{
echo 'Mail sent!';
}
$mailer->ClearAddresses();
$mailer->ClearAttachments();
also getting another error when I tried an example given in phpmailer docs # examples/test_smtp_gmail_basic.php
SMTP -> ERROR: Failed to connect toserver: php_network_getaddresses:
getaddrinfo failed: No such host is
known. (0) SMTP Error: Could not
connect to SMTP host. There was a
problem sending this mail!
so there must be setting or configuration error. there can't be code error.

Answer 1

Is SMTP set up on ? And if so is it configured to listen to smtp..com on port 587? If the server is not set up by yourself it's not uncommon that they listen to mail..com instead. Also, try to connect to port 25 to see if it might be configured to listen to the default smtp port.
The error messages is in any case very clear. The host is not responding to your connection attempt. The reason could be missconfigurations in both the server and in PHP, firewall issues, routing issues, DNS issues etc.

Answer 2

Hopefully this helps someone else out there because I was fighting this same error. First I was getting. I was getting an error that said it couldn't connect(). Then I turned on the debugging and got the error you mentioned. The solution that worked for me was to change the smtp..com to the ip address.
$mail->Host = 'smtp.whateverDomain.com';
to
$mail->Host = 'theIPaddress';
debugging
$mail->SMTPDebug = 1; // enables SMTP debug information (for testing)
// 1 = errors and messages
// 2 = messages only

Answer 3

I had this problem a while ago, everything checked out just fine but the problem persisted. A reboot of httpd.service solved it.

Answer 4

Had this issue after restart of computer where docker container with apache webserver was running.
Apache server hosted php code which stopped sending emails after computer restart.
Restarting apache docker container solved the issue.