Not possible to enter the new activation code for Plesk: page is reloading constantly

Symptoms

• When accessing Plesk UI > Key Settings it is not possible to enter the new activation code as the page is reloading constantly

• Plesk License has expired or was installed with an incorrect activation code previously

Cause

Product issue:

• #PPP-51903 "Installing an invalid Plesk license no longer makes the “License Management” page reload continuously."
  Fixed in:
  • Plesk Obsidian 18.0.34 on 09 March 2021

Resolution

Please consider updating the Plesk installation:

How to install Plesk updates

If an update is not possible for some reason please try to install the Plesk license via CLI:

# plesk bin license -i XXXXXX-XXXXXX-XXXXXX-XXXXXX-XXXXXX