I recently upgraded Zimbra from NETWORK-5.0.15 to NETWORK-5.0.21. Today I saw this in the logs
zimbramon: 28370:err: Service status change: (DOMAIN) snmp changed from running to stopped
In the Server Status inside web admin control panel
Jan 12, 2010 2.41 PM (date i stale)
I found this thread with similar problem
Is this bug present in all versions prior 6.0.2?