new 6.0 install. Everything works for a while, but then we start to get deferred messages and IMAP users start to have trouble connection. I do a server restart and all is well for another hour until the issue repeats itself. This issue only happens during the day when we have all of the users connecting to the server, after hours it works ok. I've adjusted the IMAP thread but it doesn't seem to help.
Server OS 10.5
2.8 ghz quad core xeon
4 gb ram
roughly 180 IMAP users and 20-30 Webclient users