Notifications are never sent (+91 phone numbers).

Second attempt at setting up Haven. Borrowed a SIM since starting up without a secondary SIM in the Haven device doesn't seem to be supported. The borrowed SIM has been verified to send / receive SMS. Updated the Haven app to the latest Play Store release.

Current status:

1. Signal never sends notifications.
2. If I click on "Signal Number (Local)", it gives me options to cancel or register, but no place to enter a new number. It has the correct number for the SIM saved from the previous setup attempt.
3. Clicking on "Register" does nothing.
4. Clicking on "Cancel" does nothing.
5. Neither notifications nor a Signal verification code ever show up on the device notifications are supposed to be sent to.
6. I see events being logged in Haven, and it's recording photos if I move in front of the camera (or shake it around, etc). It just never sends a notification.

Does this work with Indian phone numbers at all? Both the sending and receiving device are at +91 number; is that an issue?

Edit, other stuff I've tried:

1. Both devices can send / receive SMS.
2. Haven device was manually registered for Signal with the same number (as the SIM), worked fine, can now send / receive Signal messages.
3. Haven still does nothing if I try to register the number with Signal, still sends no notifications even when events are being logged.