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>

or

PLESK_ERROR: 502 Bad Gateway

or

PLESK_ERROR: ERROR Failure failed to parse timeText

or

Unable to remove subscription in Plesk. The following error appears in panel.log:

CONFIG_TEXT: 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>

If there are no errors 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>

or

The license is in grace period even though it was updated/renewed correctly on a licensing server side:

PLESK_WARN: You are currently operating within the grace period of your product license. To update your product license, select the Retrieve Keys option on the License Management page.

While trying to retrieve/install keys at the page Plesk > Tools & Settings > License Management it does not load and fails with the following error:

PLESK_ERROR: 504 Gateway Time-out (nginx)

Cause

Corrupted Fail2ban packages. When Plesk backend tries to get the service status for fail2ban, the process hangs and returns a timeout error.

Resolution

1. Log into Plesk UI and stop Fail2Ban service in Plesk > Tools & Settings > Services Management.
2. Connect to the server using SSH.

3. Remove all Fail2Ban logs:

   # rm -f /var/log/fail2ban*

4. Open Plesk UI, go to  Tools & Settings > Updates & upgrades > Add/remove componetns > reinstall Fail2Ban component.

Additional Information

• How to install Plesk additional components