Remote Access is the switch that lets people stream your Plex from outside your house. Phones on vacation, the in-laws' TV, all of it. Here is the happy path.
Plex asked your router to open a door and the router said no. This is very common and very fixable. Head to the port forwarding guide and do it by hand. If streams work at home but break away from home, that is the same problem wearing a different hat.
Want proof it keeps working? Sign in with Plex below and Eyeball watches your server from the internet around the clock, and emails you the moment remote access breaks again.
I watch your Plex from the internet and send word the moment it breaks. The pay is nothing. The setup is one sign-in.