mysqli_connect(): (HY000/2006): MySQL server has gone away - php

Question

I get this error:
Warning: mysqli_connect(): MySQL server has gone away in C:\Apache24\htdocs\soccer.php on line 5
Warning: mysqli_connect(): Error while reading greeting packet. PID=19176 in C:\Apache24\htdocs\soccer.php on line 5
Warning: mysqli_connect(): (HY000/2006): MySQL server has gone away in C:\Apache24\htdocs\soccer.php on line 5
Fatal error: Maximum execution time of 30 seconds exceeded in C:\Apache24\htdocs\soccer.php on line 5
when trying to run a php file on localhost.
php7.2 MySQL 8
i have tried alot of suggested soltutions on for hours but no success.
here is the PHP code which i am just using for other purpose and dont understand all of it but just because i want to connect a database to may Application
<?php
$con = mysqli_connect("localhost:81","root","root","testdb") or die ("could not connect to mysql");;
if(mysqli_connect_error($con))
{
echo "Failed to connect";
}
$query = mysqli_query($con,"SELECT * FROM testtb");
if($query){
while($row=mysqli_fetch_assoc($query))
{
$flag[] = $row;
}
print(json_encode($flag));
mysql_free_result($query);
}
mysqli_close($con);
?>

Answer 1

Mysql Server use 3306 port as a default. You are trying to connect with Mysql 81 port and Mysql refused to connect with that port. So change
$con = mysqli_connect("localhost:81","root","root","testdb") or die ("could not connect to mysql");;
to
$con = mysqli_connect("localhost:3306","root","root","testdb") or die ("could not connect to mysql");;
By the way yo don't need to write port. 3306 is default.
$con = mysqli_connect("localhost","root","root","testdb") or die ("could not connect to mysql");;

Answer 2

well for some reason i used 127.0.0.1 instead of localhost and worked Thanks anyway for the help.

Answer 3

if you are using xampp then check the port number of mysql server and change
this ---->>
$con = mysqli_connect("localhost:81","root","root","testdb")
to ---->>
$con = mysqli_connect("127.0.0.1:3306","root","root","testdb")
In the place of 3306 you can put your mysql server port number.