Hello @Matthew
Welcome to the Microsoft Q&A Platform, and thank you for reaching out. I hope you are doing well.
I understand you’re experiencing trouble logging into your account. It appears that receiving a code via email works for MFA, but the SMS option to your phone number is not functioning.
Since you received text messages when recovering your username, it seems your phone number is correctly registered.
To confirm, is the login issue occurring only when using SMS for verification?
Please follow the steps below to check which authentication methods are registered to your account.
- Visit My Sign-Ins | Security Info | Microsoft.com. You will be prompted to log in with your credentials. After entering your account details and password, a page will open as shown in the picture below.
- In the Security Info tab, review the available sign-in methods for your account.
- Please verify that your phone number is correctly registered to your account.
- If possible, remove the existing number and try adding it again.
- I also recommend adding Microsoft Authenticator as a sign-in method for your account.
- To add a new sign-in method, select "Add sign-in Option" as shown in the screenshot above and follow the on Screen instructions.
This method allows you to view and update the security information for your account.
If you have any questions, please let me know. Thank you.