Resolved Watchdog says Plesk Web Server down since 18.0.79

[King555]

Server operating system version

Ubuntu 24.04.4 LTS

Plesk version and microupdate number

Plesk Obsidian 18.0.79 Web Admin Edition

I just upgraded Plesk to version 18.0.79 and now the Watchdog extension says that the Plesk Web Server service is down, which is obviously not the case, because I can access Plesk.

I guess it has something to do with with my custom Plesk port. After the upgrade the two config files with the ports were overwritten and had the default ports. Now I set them back to my custom port and restarted Plesk. But before the upgrade I also had the custom port and disabled the default ports in the config files. What changed?

 

[Sebahat.hadzhi]

Hi, @King555 . Could you please check if any errors are being logged at /var/log/plesk/modules/monit.log?

 

[King555]

Here are the last 50 lines of that file:

[2026-06-29T08:44:21+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T08:46:21+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T08:46:21+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T08:46:21+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T08:46:21+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T08:48:21+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T08:48:21+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T08:48:21+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T08:48:22+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T08:50:22+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T08:50:22+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T08:50:22+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T08:50:22+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T08:52:23+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T08:52:23+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T08:52:23+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T08:52:23+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T08:54:23+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T08:54:23+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T08:54:23+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T08:54:23+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T08:56:24+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T08:56:24+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T08:56:24+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T08:56:24+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T08:58:24+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T08:58:24+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T08:58:24+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T08:58:24+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T09:00:25+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T09:00:25+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T09:00:25+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T09:00:25+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T09:02:25+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T09:02:25+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T09:02:25+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T09:02:26+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T09:04:26+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T09:04:26+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T09:04:26+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T09:04:26+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T09:06:26+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T09:06:26+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T09:06:26+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T09:06:27+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T09:08:27+0200] error    : 'plesk_apache' failed protocol test [generic] at [localhost]:8443 [TCP/IP TLS] -- Connection refused
[2026-06-29T09:08:27+0200] info     : 'plesk_apache' trying to restart
[2026-06-29T09:08:27+0200] info     : 'plesk_apache' stop: '/bin/systemctl stop sw-cp-server.service'
[2026-06-29T09:08:27+0200] info     : 'plesk_apache' start: '/bin/systemctl start sw-cp-server.service'
[2026-06-29T09:10:28+0200] error    : 'plesk_apache' service restarted 1000 times within 1000 cycles(s) - unmonitor

 

[King555]

After seeing the log entries I added listen 127.0.0.1:8443 ssl default_server; to /etc/sw-cp-server/conf.d/plesk.conf (the file still includes the line listen 127.0.0.1:8880 default_server;). And this time I did not only run service sw-cp-server restart, but also service sw-engine restart.

It seems that these two things solved my issue.