My Zimbra found the problem with the message below;

stale pid xxxxx found in /opt/zimbra/log/zmmailboxd_manager.pid: No such process

Jul 20 10:41:02 messaging zmmailboxdmgr[1408]: stale pid 23847 found in /opt/zimbra/log/zmmailboxd_manager.pid: No such process
Jul 20 10:41:02 messaging zmmailboxdmgr[1408]: assuming no other instance is running
Jul 20 10:41:02 messaging zmmailboxdmgr[1408]: file /opt/zimbra/log/zmmailboxd.pid does not exist
Jul 20 10:41:02 messaging zmmailboxdmgr[1408]: assuming no other instance is running
Jul 20 10:41:02 messaging zmmailboxdmgr[1408]: no manager process is running

After the message shown, Zimbra Mailbox will stop.

Everytimes I started the mailbox server by manual (zmmailboxdctl start),
then the users can use the email.

But the next problem is Mail Queue, I saw the many messages queue.

Now I try to solve the problem but I don't know what's the problem for STALE PID xxxx down.

I try to search about the message STALE PID and found The Stale pidfile Syndrome but I don't know how do I do.

Please advise or suggest for correct the problem.

My Server is HP Proliant
Xeon X3430, 8 GB memory, Raid 5 with 500 GB x 4

If anyone comment and advise for the best hardware and OS please send me at verapong.t@gmail.com

Very Best Thank You
Verapong.