NullReferenceException error in SuperSocket.SocketEngine.dll

Jul 23, 2016 at 5:46 AM
i used supersocket in my game server in its good but after a while my program crashed.
clients connected to the server and sending data to each other like chat.
when i debugging my program it says this error .
<An exception of type 'System.NullReferenceException' occurred in SuperSocket.SocketEngine.dll but was not handled in user code>
my SocketEngine version is 1.6.4
it says that its not in my code so i couldnt fix it.
this is my config code
Dim config = New supersocket.SocketBase.Config.ServerConfig()
config.Port = 8082
config.TextEncoding = "UTF-8"
config.Mode = SocketMode.Tcp
config.SendingQueueSize = 1000
please help me to fix this error.
thank you