Plex cannot see that this 1 video exists

Plex DocumentationYour Media
Naming & Organizing Your TV Show Files
Editing Libraries

You need to follow Plex naming requirements.

Plex Dance the entire show after renaming and reorganizing the episodes. This removes incorrect information from the Plex database.

/TV Shows  <-- TV Library points here.  Name unimportant
.../A Dog's World with Tony Armstrong (2022) <-- show_name (year)
....../Season 01 <-- "Season" in English.  Two digits for number.
........./A Dog's World with Tony Armstrong (2022) s01e01 Friendship.ext  <-- ext = mkv/mp4/etc

Also, it is a new TV show not yet entered at TVDB.com. You will need to tell either the library or the show to use TMDB for episode information.

At the library level:

  1. Edit the Library (See support doc above)
  2. Choose Advanced
  3. Choose The Movie Database for Episode Ordering
  4. Refresh the metadata for the library.

At the show level:

  1. Edit the show (click on the pencil icon)
  2. Choose Advanced
  3. Choose The Movie Database (Aired) for Episode Ordering
  4. Refresh the metadata for the show