Media Encoder "Failed" error on everything

Media Encoder worked for about 15 files, then suddenly every attempt shows as "failed" after about 1 second.

Converting 4k sony files from .mp4 to ProRes 422 LT (for easier editing in After Effects).

Any ideas on how to fix this?  I have already uninstalled and reinstalled Media Encoder and deleted preferences data.  Any help is much appreciated!