We are experiencing a problem with semi regularity on high traffic instances where cfmail stops working. We check in the tasks queue and they seem to be stuck there, however I can verify that the mail instance is working as we send some mail through Java and it works without incident even as lucee is in a "stuck" state.
Strangely we can reexecute the failed tasks through the admin and that will typically clear it. We are having a hard time reproducing as it only seems to happen on high volume but it is unfortunately fairly regularly (after a server has been up for a few days).
I've seen a few other reports of this such as https://groups.google.com/forum/#!topic/lucee/KXIwL0rFxl4 that sound very similiar
But no clear resolution. Any ideas for troubleshooting? We are currently attempting to build a page to recreate the issue but I wanted to go ahead and submit this to see if you were aware and had any ideas. Thanks as always!