I saw the post here about the Red X but had another question.
The file plays fine and I can edit tags, however it seems Plex refuses to see it as part of the series (this is book 2 in a 2 book series) and separates the books out when I view it in Plex.
I use the “Album” field in MP3Tag to group multi-book series together in Plex.
Not a big deal just curious. This is the first time I’ve seen the “X” and the first time Plex gave me this issue.
The red x indicates that there is trouble reading the tags.
So I would take measures to get proper tag data first and then investigate the other problem.
Perhaps it is also gone once the red x is gone.