There are two basic types of situations when this issue occurs in Plesk Panel:
The watchdog module fails to activate IMAP/POP3 Server monitoring.
The watchdog module fails to start when IMAP/POP3 Server monitoring is activated.
When trying to activate IMAP/POP3 Server monitoring by the Watchdog, it fails and says the service is stopped but it can be started.
# less /usr/local/psa/var/modules/watchdog/log/monit.log
'courier_imap' trying to restart
'courier_imap' stop: /etc/init.d/courier-imap
'courier_imap' start: /etc/init.d/courier-imap
'courier_imap' failed, cannot open a connection to INET[127.0.0.1:110]
Collector: cannot open a connection to http://127.0.0.1:2912/ -- Transport endpoint is not connected
Collector: no server available -- aborting message
When trying to enable the Watchdog module, the following error appears in logs:
# tail -f /var/log/messages
[213944.684542] monit: segfault at 800b2cc ip 0805d0d8 sp bfffda80 error 4 in monit[8048000+45000]
[213944.927657] monit: segfault at 800b2cc ip 0805d0d8 sp bfffe080 error 4 in monit[8048000+45000]
# tail -f /usr/local/psa/var/modules/watchdog/log/monit.log
Starting monit daemon with http interface at [127.0.0.1:2911]
Starting monit HTTP server at [127.0.0.1:2911]
monit HTTP server started
The courier-imap was modified with the Micro-Update.
/usr/local/psa/admin/bin/modules/watchdog/monit needs to be replaced with the attached one that corresponds with your OS and Architecture.
Note: Back up the original file and rename it to
This problem has been fixed in Parallels Panel 10.4. Consider upgrading Parallels Panel on your server.