I haven't found this to be the case. I use the free plex server on Windows and MacOS, and connect to my home boxes from my phone. Prior to April 2025, I could stream on my phone from my Plex servers anytime. Since the last update, attempting to stream from any device that's not on the same LAN as the server pops up a window asking you to subscribe if you want to stream "remotely". This is even in cases where nothing is being sent through Plex's servers except for signaling data. It is only possible to stream over the internet for free now if you tunnel to that server, make it your tailscale exit node, and use the web app, not the mobile app.

I'm not sure what the deal is with Plex Home but maybe they grandfathered in some kinds of older accounts. At this point though, it no longer appears to be a free option to easily stream from your home server if you're setting it up fresh or have a regular account.

Are you connected via the same account or a separate one added to as a friend or whatever?