Help - Error "Conversion failed. The transcoder failed to start up."

[FordGuy61]

There are multiple threads on the topic.

Current workaround is to map to a drive letter instead of using UNC.

Latest update I’ve seen from Plex is a fix is scheduled for 1.20.4:

Subtitles on UNC cannot be found

There is a fix for this coming in the next beta release (1.20.4) which should be available in a few weeks.