Unable to manage WordPress instance in Plesk: Unable to locate configuration path

Symptoms

• The following error is shown for a WordPress instance in WP Toolkit :

  PLESK_ERROR: {"err_code":40002,"err_message":"Unable to locate configuration path"} PHP Notice: Undefined variable: exit in /usr/share/plesk-wp-cli/php/class-wp-cli.php on line 503 PHP Notice: Undefined variable: exit in /usr/share/plesk-wp-cli/php/class-wp-cli.php on line 505

• The similar error is shown when enabling Switch to HTTPS in Plesk at Advisor > Recommendation > Secure WordPress Sites for the affected WordPress instances:

  PLESK_ERROR: Cannot switch from HTTP to HTTPS: Execution extension has failed with exit code 3, stdout: , stderr: ERR [util_exec] proc_close() failed ['/usr/local/psa/admin/bin/filemng' 'example' 'exec' '/var/www/vhosts/example.com' '/usr/local/psa/admin/plib/modules/wp-toolkit/vendor/wp-cli/wp-cli/bin/wp' '--path=/var/www/vhosts/example.com/httpdocs' 'search-replace' '' '' '--skip-columns=guid'] with exit code [66] Unable to locate configuration path {"err_code":40002,"err_message":"Unable to locate configuration path"}

• The following entry can be found in /var/log/plesk/panel.log:

  CONFIG_TEXT: An error occurred while executing WP-CLI command for instance: WordPress instance #134 ('/httpdocs')

Cause

WordPress instance is corrupted and has missing directories/files.

Resolution

WP Toolkit finds all actual/removed WordPress installations by wp-* mask inside of domain's webspace directory.

1. Log in to Plesk.
2. Browse to Domains > example.com > File Manager and check the content of the WordPress installation directory.
3. If it is empty or accidentally completely removed, restore the website from a backup.
4. If the installation was removed previously directly from the file system on purpose and orphaned file/directories are remained, like wp-content folder, detach the instance and perform a new scan:
   • Browse to WordPress extension and Detach it:
     
   • Scan for installed WordPress instances: