Is there something up with TVDB? Plex suddenly doesn’t seem to be able to pull metadata for a series that it’s definitely been able to in the past. Been trying for the last day nearly and no joy no matter how many times I try. All the episodes are named correctly and Plex sees them but doesn’t show episode details (named episode 1, 2, etc. instead of the actual name it’s shown before), just the file’s own data.
I’ve been shuffling some files around here and had to refresh metadata on a series to get some blanks filled in just now, and it worked for me. Might give it another shot in case it was a short blip on their end.
Hey, so I have run into this lately too. I think it is another result of the enhanced security settings of some browsers. I haven’t found a way to fix it yet, but based on how the TVdb names the files you’re looking for (i.e. banners, posters, etc) these flag the pop-up and content filters. So I’ve been able to ‘fix’ the issue by using The Movie Database instead for TV shows that have issues pulling new data.
I have uBlock Origin and Disconnect both active on app.plex.tv, and pop-ups blocked, too (not on purpose, just standard settings) and I don’t have any issues. If this was really an issue with such filters, wouldn’t the solution be to just unblock/whitelist for app.plex.tv domain?
Since the request to the TVdb is going through the API via the Plex server, I don’t think your web browser settings can impact it. 
