I get UNAVAILABLE error all the time when I try to call Firebase Cloud Function in React Native Android App.

I installed React Native Firebase exactly as it is described here:
https://rnfirebase.io/

I asked ChatGPT and Claude where can be a error but none of them see any error, they just repeat the manual from https://rnfirebase.io/

Just don’t have any other ideas what may be wrong.

Please advise.

P. S. When I run exactly the same React Native code on iOS everything works fine. The problem is only on Android. So I think the problem is with some Android app settings in the project, not with React Native code.