You must delete any existing authentication setting in the Authenticator app on the new phone and then register the device as your authenticator. Please follow the steps below:

1. Take your new phone to a computer and login to Outlook on the pc by using a browser to navigate to outlook.office.com
2. Once Outlook is open click your initials in the top right then click "View Account" in the drop down.

3. In the screen that opens, click on Security Info tile, click "UPDATE INFO"
4. On the Security Info page, click the "+Add Sign-in Method"
5. Choose the "Authenticator" as your method. 
6. Click "Next" twice
7. Now on your new phone, go to the authenticator app and tap the + sigh at the top
8. Select "Work or School Account"
9. Tap "scan a QR Code"
10. Scan the code on your computer screen
11. Complete the Authentication Prompt.


Login to Outlook on your phone
1. Open outlook
2. Click add new account
3. Select Exchange account
4. Enter your email details
5. authenticate