I used to use my mobile phone number to receive an SMS for two factor authentication.
It worked fine, but it took a while to receive the SMS. So I decided to setup the usage of an authenticator app instead. The box website first requested me to remove two factor authentication via sms first, before I could select another method, so I removed SMS.
Then when I tried to set up the authenticator app, the QR code would not display! I tried multiple times, till I finally gave up.
Then when I tried to reenable SMS again, it said that my phone number was an invalid phone number, despite it being the exact same number that I have used for years, and worked fine until I removed it a few minutes ago. Now I can't even get back the SMS two factor authentication that I was using before I tried enabling the app.