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've just had this same error on setup of a first time key. It turned out that Plesk does not like spaces in the label at the end of the key.
i.e. the key ended in "New Key for MySite" and I had to change it to "NewKeyforMySite" - once I did that, the key manger page worked,
For anyone else looking for the mysterious icon, it's top right and used to expand/collapse the right hand panel.
There are screenshots in this thread: Resolved - How to work with SSH Keys Manager