And yet the ring app works fine. The second you go back to WiFi both Ring and Rapid app work. I have uninstalled both apps, no change.
Rapid App use to work once, on the same phone.
Hi @JJVV. That’s definitely odd as the Ring App and Rapid Ring App should still work properly whether on wifi or on cellular data. If you have a VPN or anything like that, make sure it’s disabled when you’re accessing the Rapid Ring or Ring App as this will impact it. If this issue continues to persist, you may want to contact your cell phone provider to ensure there are no settings with your cellular data that could be preventing you from using certain apps. 
There is no VPN, the iPad works fin with the rapid app on the same provider and same cell plan. Also the normal Ring app works fine. If you Google it, its a fairly common complaint…
@JJVV You can also reach out to our support team at one of the numbers available here if your cell phone provider doesn’t find anything out of the ordinary regarding your cellular data plan. We’re taking additional steps to protect our team and help reduce the spread of COVID-19, so this has resulted in longer than normal wait times. If you are outside of the US, please read our response to COVID-19 here to see how to contact support.
Its OK, I deleted the app and returned the extra camera I had bought… Seems like it’s an ongoing issue with no resolution form my research. If there are the amount of complaints about it, and not a clear answer or resolution by now, there never will be…
I am having the same problem, can’t access rapid ring on mobile data but can connect no problem on wifi. The main ring app works fine it’s just the rapid ring.
My ring doorbell is connected permanently at home to virgin media but I was told Rapid Ring was not compatible with virgin media security WP2 (whatever that means!) and I should create a guest network in my hub settings and disable any security or passwords! But that didn’t sound like a good idea to me!
Can anyone help resolve this
also contacted my mobile network provider to see if they were blocking me using the app and they said there was no possible way for them to do that.