setting up centurytel mail on iphone

I have the 3GS iphone. I'm trying to setup my centurytel email. I can successfully send emails, but I can't receive incoming emails.

Incoming Mail Server: mail.so.centurytel.net
Outgoing Mail Server: smtpauth.centurytel.net

Using SSL is set to OFF

Authentication is set to Password

IMAP Path Prefix is set to /

Server Port is set to 993

It says the server is not responding?

But, I can send emails fine.

Thanks for any help.