My Capital One "Convert Rewards" was working fine until my SO and I got new devices on T-Mobile and Capital One 2FA is not working for me. If I use SO's number for 2FA on my Capital One account, it works fine. The T-Mobile business account is under my name not SOs. So, getting a new device theory discussed on here is partially correct.

I have spent numerous amount of time on the phone with Capital One and T-Mobile trying to resolve the issue. Capital One has closed my tickets stating that they can not do anything until their system decides to register my name and phone number.