Since upgrading to Moodle 4.4 (Build: 20240422), I'm getting task failures: 

Fail delay: 1 day - Cleanup of unverified incoming email (tool_messageinbound\task\cleanup_task)
Fail delay: 1 day - Incoming email pickup (tool_messageinbound\task\pickup_task)
Fail delay: 1 day - mod_forum\task\send_user_notifications ID = 155
Fail delay: 1 day - mod_forum\task\send_user_notifications ID = 179
 

There is a forum entry which seems to describe the same issue I'm having: 

https://moodle.org/mod/forum/discuss.php?d=458257

Everything else on the site seems to be working as intended. This issue did not occur prior to upgrading to 4.4