Looks like I’ve finally rooted out the cause of Gentoo’s IMAPS servers returning ‘SSL errors’ in Apple’s Mail.app. It turns out that the way I had configured Mail to check for new messages every minute was not so friendly to Gentoo’s IMAPS server. Increasing said configuration value to every five minutes seems to have fixed the problem.
This problem had been bugging me for a while. Generally, all that was needed to fix it was to force a new connection attempt, and everything would work for a few seconds afterwards. Oddly enough, none of the other IMAPS servers that I use had this problem (even though my own server uses the same courier-imap software as Gentoo’s).
Seems like everything is in working order now. I just thought I might get my ’solution’ up on the web for anyone else that’s having the same issue.
Instead of polling your server, try this excellent imap push plugin for mail.app: http://www.rothwell.us/imapidle/index.html