When you look in your Profile to verify that the correct number is stored in the Mobile number field, do you see "Automated calls and texts are allowed"?
Yep! I've been through all of that stuff. Thanks for suggesting. I've enabled texting to my number for every possible feature and alert, but to no avail.
While I was going through all that, I found the option to generate a virtual card. That also fails with the same 2FA error I get trying to transfer miles.
I've removed and then re-added my phone number in the Profile section in the hope that it will be reprocessed, based on folklore I'm hearing from one or two tech support people.
One more thing that's really amazing is that 9 out of 10 support people think that I want to book travel, and try to transfer me to Cap1 Travel, even after I've patiently (honest!) and clearly explained the feature to transfer points to airlines. The other person thinks I want to transfer points between cards.