Issue courier_pop3s failed, cannot open a connection to INET[localhost:995]

[flash5k]

PRODUCT, VERSION, OPERATING SYSTEM, ARCHITECTURE
Plesk v12.5.30_build1205150826.19 os_CentOS 6, CentOS 6.8 (Final)

PROBLEM DESCRIPTION AND STEPS TO REPRODUCE
Courier-pop3s crashes every 2-4 minutes while Watchdog is running.
Disabling Watchdog allows the service to run without problems.

ANY ADDITIONAL INFORMATION
In /usr/local/psa/var/modules/watchdog/log/monit.log:

[MST Nov 9 18:26:38] 'courier_pop3s' start: /usr/local/psa/admin/bin/mailmng-service
[MST Nov 9 18:31:40] 'courier_pop3s' process is running with pid 23892
[MST Nov 9 18:31:40] 'courier_pop3s' failed, cannot open a connection to INET[localhost:995]
[MST Nov 9 18:31:40] 'courier_pop3s' stop: /usr/local/psa/admin/bin/mailmng-service
[MST Nov 9 18:36:44] 'courier_pop3s' process is not running
[MST Nov 9 18:36:44] 'courier_pop3s' trying to restart

The output from openssl s_client -connect mail.myserver.com:995:

CONNECTED(00000003)
---
New, TLSv1/SSLv3, Cipher is ECDHE-RSA-AES256-GCM-SHA384
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
SSL-Session:
Protocol : TLSv1.2
Cipher : ECDHE-RSA-AES256-GCM-SHA384

Keys in config match actual location => /usr/share/pop3d.pem /usr/share/imapd.pem

 

[IgorG]

Plesk check this KB article https://kb.plesk.com/en/128623

 

[flash5k]

I have checked out article https://kb.plesk.com/en/128623, https://kb.plesk.com/en/128617 and followed the instructions there before I posted. Did I miss something?

 

[IgorG]

What about output of

# openssl s_client -connect localhost:995

?

 

[flash5k]

I did that because of article 128623 to test if I could connect using TLS protocols after making sure that the config file directive TLS_PROTOCOL=TLSv1+ was set. Watchdog still causes pop3s to crash. The output appears to me like it's working correctly. Do you see something in the output that would indicate otherwise? I even replaced the .pem files with the originals to make sure my certs weren't corrupt. I don't know how Watchdog interacts with pop3s that would cause it to crash.