- Plesk Onyx 17.5 for Linux
- When switching PHP handler from FPM application served by Apache to FPM application served by nginx at Subscriptions > example.com > PHP Settings it reverts back after clicking OK/Apply .
- Proxy mode is enabled in Subscriptions > example.com > Apache & nginx Settings.
- There is an empty string while selecting PHP handler
Please consider updating your server:
If update is not possible for some reason you may try the following
- Connect to the server using SSH.
- Install all the available Plesk updates using Plesk installer.