Everything in library is Aqua Teen Hunger Force?

No, you haven’t.
17. Arrow - S06E017 - Brothers In Arms
is not a compliant file name.

And the folder structure where those files live in is also very important in Plex.
If you introduced additional, arbitrary folder levels here, those kind of mismatches can happen.

So please look at the properties of your library and see at which folder you have pointed your tv show library.
Underneath this ‘main’ folder there have to be only folders and subfolders as described in the above linked guide. No more levels, no less levels.

If your files are mp4 or m4v, you also want to perform these steps:
Go to

  • Settings - Server - Agents - Shows - TheTVDB

In there, grab the line ‘Local Media Assets’ with your mouse and drag it downwards, so it ends up being at the bottom of the stack of active agents.
Repeat the same under

  • Settings - Server - Agents - Shows - TheMovieDatabase
  • Settings - Server - Agents - Movies - Plex Movie
  • Settings - Server - Agents - Movies - TheMovieDatabase

Once you have everything compliant, perform the Plex Dance

If you still have trouble after doing the above, please enable ‘debug logging’ and post some logs after you have performe dthe Plex Dance with one show.