I have 2 stickup cams and an old ring doorbell. On the stick up cams, When I’m on my phone network using 4G, live view DOES NOT WORK. It DOES work if I ditch the app and log in to the ring website and live view through my chrome browser. Therefore, it is clearly poor programming. For an expensive paid subscription, this should be programmed correctly and fully working. There are numerous year old threads with hundreds of unresolved posts on this but nowhere highlights that the ring website works but the apps don’t.
Sorry to hear about this, @moetmoet. Try out the Rapid Ring app, designed for the quickest access to live view, to see if this works on your mobile device cellular connection. Please also ensure there is no vpn enabled. Let us know if this works! 
Live View isn’t working for me either on the main Ring app for any of my cameras or doorbell, but is working on the Rapid Ring App. They must know something is wrong if they created a whole new app just to connect to the cameras