Is it possible that this show is “Adult”, and won’t show up unless you enable searching for adult content in your server settings?
But hard-coding in the TMDB ID into the folder like OttoKerner shows is a good way to force it. Make sure to Plex Dance the file first, to make sure it is scanned for the “first time” by Plex.
Does it appear as “unmatched” in your server, or does Plex scan and NOTHING new appears? If the former, then the above suggestions should work. If the latter, it’s a file/folder organization/structure issue and you need to correct that.