I checked the logs and it said it was assuming a remote connection because there was an unknown hostname in the headers (I forget the exact wording). It was because the hostname I was using didn’t match the hostname configured in the server’s OS (one I set up on my local DNS server).
I don’t think simply forwarding the port actually works with free Plex anymore. I think if the server has a different public IP from the client it asks you to pay, even if you’re connecting to the server over LAN.
Edit: That doesn’t appear to be true. I’m not entirely sure how Plex is checking whether you’re trying to stream remotely. In my case at least it works if I connect to my server using the LAN IP, but not if I use DNS (even though it resolves to the same IP). Maybe I’m missing something to allow it to work using the hostname.
Working “watched” labels on the Apple TV client would be nice. Not having those is a deal breaker for me considering 99% of my use case is streaming media to my Apple TV over LAN.
I have Jellyfin running along side Plex in case I want to do remote streaming, but I never use it and generally just copy the files for what I want to watch to my laptop if I’m going to be watching something away from home. Or I can just VPN in to my home network.
Personally I don’t forward ports for anything that only I am supposed to access (such as SSH). Instead I connect to my home network via VPN and establish the connection from the inside. I just have an allow all from the VPN subnet to my main one, but you could also allow things selectively if you don’t want everything accessible via VPN. Using the VPN has the added bonus of ensuring everything is going through a secure tunnel if I’m connecting from a public network.
Strange then that Google and Apple didn’t take it down. Valve made a choice and not a good one.