a few days my mail server started to exhibit this problem, repeating each 3 times a day
Email zmconfigd 16:16:24 [14446]: Service status change: xxxx.xxxxx.org.br mailbox changed from running to stopped

Because of this the server is very slow and I just need it restarts

I'm using Release 8.0.3_GA_5664.RHEL6_64_20130305090204 RHEL6_64 FOSS edition.