Unable to remove WordPress instance via Applications: Permission denied

Symptoms

• Unable to remove WordPress instances via Domains > example.com > Applications > Remove: 

  PLESK_ERROR: Permission Denied

  OR

  Page just reloads with no errors.

• In some cases, the process finishes with the message below, but the WordPress instance is still shown as unremoved: 

  {"status":"success"}

• The following error can be observed with debug enabled in %plesk_dir%adminlogsphp_error.log:

  2019-06-19 21:45:55] ERR [extension/wp-toolkit] An error occurred when dispatching action 'removeAction': Permission denied
  [2019-06-19 21:45:55] DEBUG [extension/wp-toolkit] pm_Exception: Permission denied
  file: C:Program Files (x86)ParallelsPleskadminplibmoduleswp-toolkitlibraryControllerAction.php

• Attempt to remove the instance just returns {"status":"success"} on the blank page in a browser

Cause

This issue is reported as bug ID EXTWPTOOLK-3043 which will be fixed in future updates.

Resolution

1. Log into Plesk.
2. Remove instance via WP Toolkit.