I am running zimbra "Release 7.1.1_GA_3196.RHEL4_20110527002117 CentOS4 NETWORK edition" and experiencing some random crashes.

Basically Zimbra stops working after a few hours. All users accessing it simply can't login anymore. An example of login attempt via imap:

* OK IMAP4 ready
? LOGIN example@example password
* BAD internal server error
Between LOGIN and BAD internal server error it takes a long time, almost 1 minute.

If i type the wrong password, it will return the error message immediately.

I tried checking at /opt/zimbra/log but i don't see any error messages in these logs.

I was wondering if someone experienced a similar problem and/or if i can increase the verbosity of logs to try to find the error?