Services - Mail - Unsent folder

I apparently have some bad data that is causing mail to get stuck and choke. (Rough description of my problem). No doubt it’s bad data entry of an email address that is causing this. However, kind of hard to track that down among 5000 users by looking at the data.

In the Lucee Server Admin > Services > Mail settings, there is this detail:

Time in seconds that the Task Manager waits to send a single mail, when the time is reached the Task Manager stops the thread and the mail gets moved to unsent folder, where the Task Manager will pick it up later to try to send it again.

Where exactly is this unsent folder? I cannot find anything resembling that within the WEB-INF directory. And since my mail server is not on the same server, this should be spooled somewhere within Java or Lucee, right?

Ubuntu 22.04 LTS
Java (JDK) 20.0.2
Tomcat 9.0.41


Mail that can’t be sent by Lucee is stored as a .tsk file which you can open with a text editor even though it’s some kind of object. Usually the error message is readable somewhere within the file.

Thank you! It also appears to be cleared out on a restart of services. I’m trying to find out what is causing mail to get stuck. No doubt a bad string in the email field.

You can run your email addresses through an email validation service like That will find all your bad email addresses stat. You might consider adding some validation (regex) to your forms to prevent future problems.


Thank you! Great tip on zerobounce! I do have some regex functions as well as stripping non compliant ASCII from the data entered. But, it’s never enough apparently.