If you got a new mobile device or lost your old one, you can update the authentication method for your Outlook account.

1. Open a new window in your browser. (Google Chrome, Internet Explorer, Edge, etc.)

2. Go to https://www.office.com/ and log in to your account.

3. Click on your username on the upper right side of the window.

4. Click on ‘View account’

5. Click on “Delete” to delete the device you have registered.

If you lose your device, use the "Sign out everywhere" option to secure your accounts and prevent unauthorized access.

Click on 'Lost device? Sign out everywhere' 

Then click 'Ok'. 

6. Click on ‘+ Add sign-in method’.

7. Choose on the drop-down menu ‘Authenticator app’ and follow the prompts to complete setting up.

8. Click on ‘Next’.

9. Open the Microsoft Authenticator application on your phone. 

10. Click on 'Next' and scan the QR code provided.