Firebase Auth – Unable to Add Phone Number for Testing

Long story short, I was using my personal phone number as the number for test; which I successfully used on a previous Firebase-backed project with the same feature. I removed the test phone number from the Firebase project as I had finished testing the feature. I think it very well may be a bug on Firebase’s end

I was successfully able to use the phone number “+1 111-111-1111”

UPDATE:

After successfully using the ‘+1 111-111-1111’ phone number, deleting it, and trying to re-enter it, I was greeted with the same error