Unable to access Fail2ban settings: Timeout of 10 seconds has been reached. Lock 'service.fail2ban' is already owned by another process with pid <unknown>

Symptoms

• While accessing Plesk > Tools & Settings > IP Address Banning (Fail2Ban), one of the following errors appear:
  

  PLESK_ERROR: Internal error: f2bmng failed: ERROR:f2bmng:Timeout of 10 seconds has been reached. Lock 'service.fail2ban' is already owned by another process with pid <unknown>

  PLESK_ERROR: 502 Bad Gateway

  PLESK_ERROR: Unable to remove subscription. The following error occurs in panel.log:

  PLESK_ERROR: Internal error: f2bmng failed: ERROR:f2bmng:Timeout of 10 seconds has been reached. Lock 'service.fail2ban' is already owned by another process with pid <unknown>

  PLESK_ERROR: ERROR findFailure failed to parse timeText

• Unable to login to Plesk UI - page keeps loading.
• If no error is shown at Plesk > Tools & Settings > IP Address Banning (Fail2Ban), the following record appears in /var/log/plesk/panel.log:
  

  CONFIG_TEXT: stderr: ERROR:__main__:Timeout of 10 seconds has been reached. Lock 'service.fail2ban' is already owned by another process with pid <unknown>

Cause

Incorrect/Incomplete installation of Fail2ban packages. When Plesk tries to get the service status for fail2ban, the process hangs and returns a timeout error.

Resolution

1. Stop Fail2Ban service in Plesk > Tools & Settings > Services Management
2. Connect to the server using SSH.
3. Delete all Fail2Ban logs:
   

   # rm -f /var/log/fail2ban*

4. Reinstall Fail2Ban using Plesk Installer.

Additional Information

How to install Plesk additional components