So when setting up this Phone Number auth with Firebase I ran into an error that said something like the SMS region (I was using +51, Peru) has to be allowed/enabled I went to Firebase Console (https://console.firebase.google.com/project/[your-project-id]/authentication/settings) and saw that it should be working because Deny was selected (with no region denied). Then, to solve it I switched it to Allow. Then selected Peru. To solve it further, then, I selected Deny. Then selected Unknown Region..