Such an annoying problem, especially for connecting to GMail via IMAP. I constantly get the error: Too many simultaneous connections. The worst part is this has been known ever since Leopard shipped:
http://discussions.apple.com/message.jspa?messageID=5820548
http://discussions.apple.com/thread.jspa?threadID=1207290&tstart=30
Any fix, Apple?
UPDATE
This problem seems to date much further back then Leopard. I’ve found references to this same issue in late 2003 (v10.3!!), here:
http://www.macosxhints.com/article.php?story=20031130150826388
Unfortunately, I don’t have access to server configuration as my problem is with GMail. It seems like Apple may never fix this…