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.
FYI you can definitely watch while your network is offline. You just net to tell it that you're happy with that (it's not activated by default for security reasons).
In your Plex server settings, go to Network, enable "Show Advanced".
Near the bottom, find the textbox that says
List of IP addresses and networks that are allowed without authIn this field, enter the local IP address of any Plex client(s) you want to keep using if your internet (or the Plex cloud) is down.
A example:
192.168.0.50Save the setting, done.
#Important thing to be aware of:
What this setting does is tell your local Plex server to simply give any Plex client that connects from that specific IP full admin access to your Plex server, ignoring any account restrictions. This means that if you have things in place to restrict access to some libraries (kids blocked from 18+ movies etc) those restrictions will have no effect. Also if you have the option set to allow file deletion, then any client from that IP could also delete items. And they could of course change any settings in your Plex server. So your kids can watch anything on your server, if you have a guest in your network and they browse to the Plex web interface, they can mess with things.
Because of that I would recommend to limit the amount of IP's you enter in that field to the absolute bare minimum. For example, only whitelist the "main living room device" plus one device you to admin the server, such as a laptop.
If you want to whitelist multiple devices, this is a example:
If you want to whitelist a entire network, these would be examples:
And of course those involved network devices should use static IPs in your home network.