A problem no one seems to be able to have an answer for

Im still having the problem of not being able to retreve my emails because of a port 110 problem. I think it is probably because of the internet settings that i have no control over but it did work until around the time i installed the 2007 security updates.

The server error encountered was: The server "pop.1and1.co.uk" cannot be contacted on port 110.

It works for about an hour every week at a random time but other than that it just give me that message in a split second, as i click get mail i get the message straight away. Doesnt even look like its trying to connect.

It does work fine over Airport though. What could possibly cause it not to work over ethernet when it used to be fine?

thanks for any help,
Steve Cooper