said by mdurkin:That may coorespond with when gmail changed their servers to be very strict about SSL certificates when popping email. I think it was around December 11th. If it didn't like the SSL certificate for some reason, it would refuse to continue with the session. For example self-signed certificates suddenly didn't work, and other discrepancies could also make it fail... perhaps you had given gmail a hostname for the POP server that didn't match the SSL certificate. Gmail did this without warning and it caused problems for a lot of folks; there were threads on google's own forums complaining about it, especially that the change was made with no notice at all. There may be more than one thing going on in your case.
The SSL certificate problem may be spot on. My Windows and Linux email servers poll some AT&T/Yahoo! accounts, and the server logs frequently have SSL certificate warning entries for the AT&T/Yahoo! email servers. In my case, the local email servers just log the warnings and continue, but Google may indeed handle it differently for "POP'd" email accounts.