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
Out of interest, do you run Roundcube?
If you look at this thread: Question - Plesk Obsidian and PHP 8 compatibility
You'll see, that with effect from Plesk Obsidian 18.0.49, Roundcube runs on PHP 8.0. So ...IF... you fall into the criterea that's covered in that thread, then that might be a cause of the issue that you've experienced. From our own past experience, we had a similar error (but on earlier PHP and Roundcube releases).