Laravel web sockets automatically stopped

Question

I am using beyondcode/laravel-websockets to implement web sockets functionality in Laravel. I am using supervisor in Apache server to run processes for database queues and web sockets. It was working fine until one day I realized that It has stopped working. I haven't made any changes to supervisor.conf file.

This is my supervisor.conf

[program:laravel-worker]
process_name=%(program_name)s_%(process_num)02d
command=php /var/www/webroot/ROOT/artisan queue:work --tries=3
autostart=true
autorestart=true
stopasgroup=true
killasgroup=true
user=apache
redirect_stderr=true
stdout_logfile=/var/www/webroot/ROOT/worker.log
stopwaitsecs=3600
startsecs=0

[program:websockets]
process_name=%(program_name)s_%(process_num)02d
command=php /var/www/webroot/ROOT/artisan websockets:serve
numprocs=1
autostart=true
autorestart=true
user=apache

When I try to start all supervisor processes using command supervisorctl start all, I get the following output:

laravel-worker:laravel-worker_00: started
websockets:websockets_00: ERROR (spawn error)

Based on this, I manually started the web sockets from my root directory using php artisan websockets:serve and I got below error:

Starting the WebSocket server on port 6001...

   RuntimeException 

  Failed to listen on "tcp://0.0.0.0:6001": Address already in use (EADDRINUSE)

  at vendor/react/socket/src/TcpServer.php:184
    180▕                 // @link https://3v4l.org/3qOBl
    181▕                 $errno = SocketServer::errno($errstr);
    182▕             }
    183▕ 
  ➜ 184▕             throw new \RuntimeException(
    185▕                 'Failed to listen on "' . $uri . '": ' . $errstr . SocketServer::errconst($errno),
    186▕                 $errno
    187▕             );
    188▕         }

      +17 vendor frames 
  18  artisan:37
      Illuminate\Foundation\Console\Kernel::handle(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))

As mentioned in the exception, the port I am using for web sockets i.e. 6001 is already in use. I listed the used ports using the command netstat -tulpn and it shows that 6001 port is being used by php. This is the output:

(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      -                   
tcp        0      0 0.0.0.0:443             0.0.0.0:*               LISTEN      -                   
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      -                   
tcp        0      0 0.0.0.0:6001            0.0.0.0:*               LISTEN      23974/php           
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      -                   
tcp6       0      0 :::111                  :::*                    LISTEN      -                   
tcp6       0      0 :::80                   :::*                    LISTEN      -                   
tcp6       0      0 :::22                   :::*                    LISTEN      -                   
udp        0      0 0.0.0.0:111             0.0.0.0:*                           -                   
udp        0      0 0.0.0.0:749             0.0.0.0:*                           -                   
udp6       0      0 :::111                  :::*                                -                   
udp6       0      0 :::749                  :::*                                -     

I killed the process using kill 23974 but it reopens quickly and uses the same port again automatically. I am not being able to figure what exactly is using this port. I tried reconfiguring, restarting supervisor, redeploying my code etc. but nothing worked. What might be the possible issues here?