Hello,
Thank you for letting us know about this issue. Regrettably, this was a bug in the previous versions. I'm very sorry for this inconvenience. It was fixed in the 5.5 version (hotfix 5.5.4):
Error: Optimized deleting of archived e-mails prevents "Out of memory" exceptions.
The Clean e-mail queue task isn't executed correctly if there is a great amount of emails already in the database.
To fix the issue I would suggest you to upgrade your system and apply the hotfix.
If you don't want to upgrade, you can the delete emails from the database (CMS_Email table) manually. The Clean e-mail queue scheduled task should delete the emails automatically, if the queue is shorter.
You can also write a
custom scheduled task to clean it manually.
Best regards,
Boris Pocatko