There’s an issue with the Cyberpanel installation using Openlitespeed on Ubuntu 18 where the PHP session files aren’t removed by the system installed.
You might see issues in your /usr/local/lsws/log/error.log like this
The cause is related to the build of of PHP session files in the /tmp folder, which usually is cleaned out by a cronjob in /etc/cron.d/php that calls /usr/lib/php/sessionclean which of course fails to running correctly due to lsphp nor working as intended.
The solution? Create a cronjob to delete the sess_ files. Here’s an example I found online
Add this code to a file an placed it in /etc/cron.daily, make sure to chmod u+x so its executable.