Playback Issues Only on Local Network

Server Version#: 1.24.4.5081
Player Version#: 4.67.0 (Plex Web), Plex for iOS (7.24.1), Plex for AppleTV (7.24.1)

Hey all, I’m at a bit of a loss with an issue I have just noticed. My Plex library is hosted on a Mac and includes a mix of m4v, mp4, and mkv files. I have noticed that some of my older content has recently stopped playing back when accessed from iOS or an AppleTV, but other content that was added more recently will playback with no issues.

My first thought was possibly corrupted files, but they will all playback just fine when accessing PlexWeb from the server Mac. In my testing, I seem to have found a major clue in that I can access the same content if I am on a cellular connection and off the local network. This tells me that the files themselves are fine and I can also verify that other (newer) files of the same type will play both on and off the local network.

Can anyone point me in a direction here for what I need to be looking at? As far as I know everything was working fine up until a couple of weeks ago. I have tried power cycling the network and the server Mac, but no dice.

Thank in advance for any assistance!

One more thing I can add is that I can sync (download) the problematic content to my iPhone whether on the network or on cellular.