Yeah, the latest snapshot is unfortunately borked.
5.3.8.49 is ok
There’s a pending patch to fix that, the change was made to validate email addresses immediately, rather than on spooling, so you get an immediate error.
Yes I started noticing this last Tuesday, when suddenly none of my emails were sending. I wasn’t aware that Lucee auto-upgrades? Is there a way I can set upgrades to manual, so I don’t get these sudden bugs out of nowhere?