Howdy, I cannot remove the configured Authenticator App from my my.norton.com account settings. The listed app/device is no longer in my possession. The Authenticator App does not have a clear edit/remove option. I’ve tried removing two-factor authentication and turning it back on and the authenticator app remains. Luckily, it is not set as PRIMARY and I’m afraid of the prominent SET AS PRIMARY button that must be avoided.
To the right of each entry for 2FA you should see a trash can icon. Clicking that will remove that method of authentication.
Be sure you have set up at least two other methods before you delete the authenticator app. Or turn off 2FA. Then set one of those as primary. Then you will see the app listed with a trash can icon.
Howdy, Peter! Thanks for the screenshot.
If I understand this correctly, I need to be accessible via two phone numbers. This is not a work account. I have only one phone number.
Could someone file a bug that this three access-method requirement makes no sense? The authenticator app listed for my account is no longer valid. It needs to be removed. requiring yet another method to remove an incorrect method makes no sense and that is one of the most likely reasons for someone to want to remove a method.
Also, as a feature request, could email be added as a 2FA method?
Re reading your OP, this app is not set as primary. So you should see the trash can icon beside Set as Primary link.
My suggestion above 2 phone numbers is not a requirement. The reason to have at least 2 methods of 2FA is that if you are only using your mobile phone for 2FA and it is lost/stolen, you will no longer have access to your Norton Account. Unless you have downloaded the one time access codes and stored them in a safe place. For security reasons, even Norton Support cannot access your Account for you. You can choose a landline ( if you still have one ), or the phone number of a friend or spouse that you trust.
Thanks again, Peter. Yeah. I still believe that forcing users to have INCORRECT information just so there are two methods is not the way to approach keeping an account acccessible. 
Maybe I’ll install an authenticator app on my tablet just so the incorrect option can be removed.