Mail 4.5 problems...

I've posted this at another location in the forum but since it was an old thread I thought I'd better do something a bit more proactive.

My problem is that Mail 4.5 is not handshaking with my mail server on my password.

I have three email accounts setup in Mail 4.5 and two work fine (one is a MobileMe account). One, however, won't remember the password and when I take the account online it asks for the password over and over and never gets connected. I'm using gmail for my server and I can access the account via the web with no problem - so the emails are there and I use the same password for both.

I read online that maybe I had reached my max on the account - checked and had 33,000 items which I cut back to 30,000 just to test - no luck.

I've repaired my keychain, etc. - no luck.

Any help would be appreciated. Thanks.