UPNP setup of Emby Server has suddenly stopped working remotely

[Luke 43099]

3 minutes ago, Beta8088Proto said:

whether or not my ISP is using CGNat (I don't pay the bill in my household and I doubt the one who does would know what that even is)

It's probably something you should look at and determine because it is happening all the time. We go over how to do that here:

Connecting from Client Apps

Quote

I am using the link exactly as the server has given me

In some rare cases the server may detect the wrong remote address. It's not an exact science, so it's a good idea to know your router's public facing remote ip address.