The cpanel-dovecot-solr service is restarting frequently with a 404 error

Symptoms

Frequent notifications are received regarding cpanel-dovecot-solr restarting, and a 404 error is cited in the notification:

Cpanel::Exception::HTTP::Server/(XID xq9rhh) The response to the <abbr title="Hypertext Transfer 
Protocol">HTTP</abbr> “GET” request from 
“http://IjFtk1HeL98AMMDQ:__HIDDEN__@127.0.0.1:8984/solr/admin/info/properties” indicated an error 
(404, Not Found)

When checking the Solr service using systemctl it shows the service as online despite the failure reports:

[root@server ~]# systemctl status cpanel_dovecot_solr
● cpanel-dovecot-solr.service - Solr for cPanel Dovecot
   Loaded: loaded (/etc/systemd/system/cpanel-dovecot-solr.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2021-05-26 21:04:41 UTC; 15min ago

Description 

The issue is caused by the cPanel monitoring service being unable to connect to the Solr service. This can sometimes be seen when an update to the Solr package fails during a cPanel version update.

Workaround

We advise ensuring the package is updated to the latest version available.

yum update cpanel-dovecot-solr

If no update is available or the behavior persists after updating, you may need to reinstall the service. The following commands can accomplish this.

Uninstall Solr:

/usr/local/cpanel/scripts/uninstall_dovecot_fts

Reinstall Solr:

/usr/local/cpanel/scripts/install_dovecot_fts