Many have recent Live View issues on cellular. I think the 2 common protocol for streaming are, UDP port-1194 and TCP port-443. I think Ring uses UDP to send video back to the phone.
I can’t make changes to my Android 11 phone cause it is not rooted. In my phone, “Multimedia message proxy & port” are not set, and might be the ones that need to change.
I tried 2 different Android free trial VPN apps, ( no payment needed ), Hide.me & PrivateVPN, and both work, only after changing APP’s Protocol Setting to TCP. Neither would work with UDP.
T-Mobile is my cellular provider, so I think the Ring APP’s are using UDP and my provider is expecting TCP.
Tomorrow I’ll contact Ring Support to see if this is the real issue and if they have a better solution than having to use a VPN for Cellular Live View.