I'm having immense difficulty with port redirection. Having figured out the weird and wonderful way of doing this by defining "games" in the Plusnet Hub One (which I am only using as I suspect a connection issue with my TPLINK) I've set up a port redirection for port 1880 so that I can access a server externally. This is EXACTLY what I do with the TPLINK and other routers and that works perfectly.
Yet, once set up, on my mobile app I can set up the internal IP of the server and it works as before - but put the external address - and it does not. Having defined the game and set up the port redirect, am I missing something? Obviously I have the actual subdomain name pointing at my Plusnet fixed IP address.