Odds-on it's physical. Either the cable, one or both the cable end plugs, the socket in the RC body or the female socket in your screen device.
The only way to narrow down the list of suspects would be to borrow (or buy) another controller to...
Good information, @Felix le Chat.
I just spent a month in Scotland and went through the process or registering myself and the Mini 4 Pro. It a bit more involved that the TRUST process, but quite reasonable and straightforward. I had no issues...