User not receiving SMS verification code
You can add a user to your account and manually verify them if they are not receiving the SMS code on their phone.
Step 1 - Add user to your account: https://www.youtube.com/embed/eAa5FyA_kKY
Step 2 - Verify the user: https://www.youtube.com/embed/4-stirg-G8o
You will then be able to grant access.