Plex trailer issue

My Plex server (recently switched to a Docker container) refused to play trailers for any of the movies stored on it.

While trying to play a trailer on Plex, this appeared:

Spent too much time looking at paths and directory permissions (it was neither), only to discover that the issue was due to me importing my existing Plex data, and the metadata getting messed up.

Turns out there was an issue has been identified with the trailer ingestion on plex.tv, and the simple solution was to refresh the metadata of a movie (or collection).

Tested this out on a single movie:

Once I refreshed the metadata, the trailer played without any issues.

To refresh an entire collection's metadata (this may take a while):

On the right of a collection name (Movies in my case), click on the ellipsis, select Manage Library, and then Refresh All Metadata.

Once that is complete, trailers should play without issue.

References

Plex - Forums - "Conversion failed. The transcoder failed to start up." https://forums.plex.tv/t/conversion-failed-the-transcoder-failed-to-start-up/742906