Scheduled Tasks execution results and other notifications are not permanently or intermittently shown on the Plesk Panel

Symptoms

• While using the Run Now button to manually run a task under Tools&Settings > Scheduled Tasks > Example Task, no notification appears for the execution results in the bottom right corner.

• Upon checking the longtasks table, one or more records are found with an status other than "done":

  # [root@server ~]# plesk db "select id, type, status, externalId, updateTime from longtasks where status!='done'"
  +-------+------------------------------------------+--------+------------+---------------------+
  | id | type | status | externalId | updateTime |
  +-------+------------------------------------------+--------+------------+---------------------+
  | 12345 | scheduler-run-task | error | 54321 | 2025-03-17 13:19:51 |
  | 12346 | scheduler-run-task | error | 54322 | 2025-03-17 14:17:58 |
  | 12347 | scheduler-run-task | error | 54323 | 2025-03-17 14:41:09 |
  +-------+------------------------------------------+--------+------------+---------------------+

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

  ERR [panel] Could not detect status for the task with ID '1234': Communication with task manager has failed: Task not found
  [ERR [panel] Control character error, possibly incorrectly encoded
  ERR [panel.ui] Control character error, possibly incorrectly encoded<br><a href='http://kb.plesk.com/plesk-error/search?metaId=5ec0f27cb9bfc363901abc5a81d6a36f&messageId=8b4590c719c09ff5c4c78feb23a01a29&file=LongTask.php&line=168&type=JsonException&version=18.0.68&message=Control+character+error%2C+possibly+incorrectly+encoded' target='_blank'>Search for related Knowledge Base articles</a>

• Sometimes a refresh of the page causes notifications to appear.

Cause

Leftover records on the longtasks table of psa database cause the tasks process to fail listing current and previous tasks notifications.

Resolution

Apply the resolution steps from this article in order to clean the leftover tasks records from the table.