Unable to create or remove domains, subscriptions, service plans in Plesk: task queued indefinitely

Symptoms

• Unable to create or remove Domains, Subscriptions or Service plans in Plesk.

• After it has been started, the task remains queued in the Plesk panel GUI indefinitely 

• The task itself is displayed as not_started in the Plesk database (psa) :

  # plesk db "SELECT id,type,status,finishTime FROM longtasks WHERE status <> 'done'"
  +------+---------------------------------------------+-------------+---------------------+
  | id | type | status | finishTime |
  +------+---------------------------------------------+-------------+---------------------+
  | 5106 | subscription-create | not_started | 0000-00-00 00:00:00 |
  +------+---------------------------------------------+-------------+---------------------+

• Applying only the solution from the How to cancel a stuck task in Plesk article removes the task, but does not prevent the issue from occurring once again

• Errors that are similar to the following appear in the /var/log/plesk/task-manager.log:

  ERROR 2024/02/27 00:00:39 task=45149 process=45149 Cannot fetch process properties: Cannot fetch 'run-plesk-task-45149.service' unit properties: dbus: connection closed by user
  ERROR 2024/02/27 00:00:39 task=45150 process=45150 Cannot fetch process properties: Cannot fetch 'run-plesk-task-45150.service' unit properties: dbus: connection closed by user
  ERROR 2024/02/27 00:00:39 task=45154 process=45151 Cannot fetch process properties: Cannot fetch 'run-plesk-task-45151.service' unit properties: dbus: connection closed by user
  ...

Cause

The entire plesk-task-manager service on the server is stuck, due to which it does not operate as expected.

Resolution

1. Connect to the server via SSH

2. Apply solution from the following article in order to cancel all stuck tasks in the Plesk task manager:

How to cancel a stuck task in Plesk

3. Restart the plesk-task-manager service on the server by executing the following command:

# systemctl restart plesk-task-manager