I tried testing a movie from my home server in plex through firefox and repeatedly got this message, even after reloading.
I knew that they had paywalled the apps on mobile and streaming from outside the network but now they have also blocked watching your own movies through your own hardware.
I do get the point that making software should be able to sustain people but I dont see the move of plex as a fair thing to do. Yes, they have made great software but taking your home server hostage feels like the wrong move.
Even a pop up that says "we need you to donate please" would have been fine. make it pop up before every movie, play donation ads before any movie but straight up disabling the app is kinda cruel.
Anyway, i have switched to jellyfin and it is insanely good. please give it a try. you can run it alongside plex with not issues (at least i had none) and compare the two.
In any case, good luck. Let me know if you need help.
Plex has pay walled FREE servers streaming to FREE clients only.
If you have a plex watch pass (for client) you're good and can stream from any server. If you have a plex pass (for server) any one can stream from your server. But you have to have one or the other.
For software I like made by people getting paid, I was happy to pay the one time fee. It's really good, secure, and downloads are fast now.
This is not true in practice, I have plexpass for my server and my wife can't watch on her phone because they want her to pay too...
She needs to update her app probably, it works fine for my wife on my server