Services unavailable

I am using iPad Air 2 with OS 15.8.4 The Ring app version is 5.83.3 I used this setup up to about 2 years ago, when the door bell was broken and then discarded. I have now purchased a new bell and trying to download the app. The App Store said download an earlier version because by IOS would not support the latest Ring app. So I have the original 5.83.3 version. When I run the app and select SIGN IN I get a message which says Ring services are temporarily unavailable, try later. Will my combination of IOS and Ring app work or should I have bought a different doorbell?