Scheduler seems to be broken after updating to 4.0

Infos:

  • Used Zammad version: 4.0
  • Used Zammad installation type: package
  • Operating system: Debian 10 x64
  • Browser + version: Firefox 89

Expected behavior:

  • Zammad fetches emails and sends notifications

Actual behavior:

  • Zammad stops checking mailbox after some time during a day and the corresponding notifications don’t come through to our preferred channel (Slack)

Steps to reproduce the behavior:

  • Upgrade to 4.0

Ever since we upgraded to the latest version (went without any issues), the scheduler has been failing permanently during a day.

scheduler_err.log only has “log writing failed. execution expired” – that’s all there is and been since the update. Googling for this error isn’t fruitful.

There are no errors in production.log, postgres logs are alright, and nothing suspicious in elasticsearch logs. Elastic works fine, Zammad front-end lets me in, although it might occasionally throw 5xx error.

Things run smoothly after restarting zammad service, but only for several hours.

Has anyone encountered this behavior? Any suggestions on how to at least fix the logging for scheduler so I can investigate further?

Thanks