iPhone 12 mini Airplay not connecting properly

[Johnny.J]

TV: GoCamp in a mobile home.
Phone: iPhone 12 Mini, ios 17.6.1
The TV works with the installed apps to watch YouTube etc through Internet Sharing on the iPhone.
Now I'm helping the owner to get this iPhone to work with Airplay to this TV using iMirror which is present on this TV.
When I click on the iMirror symbol for a TV app running on the iPhone the TV reacts by showing a play slider on the bottom of the screen which then immediately disappears and the "wheel" shows rotating indefinitely. What am I missing here?

 

[FreakinEurekan]

Do basic things like Photos app mirror okay?

If so, it could be a limitation of the video app or content, e.g. HDCP protection.

 

[Johnny.J]

Nothing mirrors! It has nothing to do with "HDCP" or whatever. It's probably a network routing question.
Does it work if the phone is not connected to a wifi but is doing internet wifi sharing only?