can't reply to newsgroup

Now I am having the following appear when I try to reply:

The host '' could not be found. Please verify that you have
entered the server name correctly.
Account: ' (3)', Server: '', Protocol:
POP3, Port: 110, Secure(SSL): No, Socket Error: 11001, Error Number:

I haven't changed anything. Does anyone know how to denter the setver name
correctly? Small steps please. I am a little lost.