I am trying to make multiple udp client / server

In my server i have

Winsock1.LocalPort = 1999
Winsock1.Remoteport = 1999
Winsock1.Bind

In my client I have

Winsock1.RemoteHost = "127.0.0.1"
Winsock1.Remoteport = 1999
Winsock1.Bind

Now my client can send my server information. But when my server try to send data back, it says Address Family Not Supported.