Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
If you are still using CentOS 7.9, it's time to convert to Alma 8 with the free centos2alma tool by Plesk or Plesk Migrator. Please let us know your experiences or concerns in this thread: CentOS2Alma discussion
I guess your issue will already be resolved.
However, if the others are facing this same problem, you can try to enable the apache status page by doing follow this link: How to enable the Apache mod_status module on a Plesk server , that may assists you locate the cause of the problem.
It's about your license. maybe license you are using is expired. Try to view panel log that located in /usr/local/psa/admin/logs/panel.log . (tail -f /usr/local/psa/admin/logs/panel.log)
I'm facing the same problem. Other website hosted loads normally and fast as lightning. But Plesk (17.5.3) is TOO SLOW! Maybe a bug? Any ideas to fix this problem?