The problem is Microsoft does not recognize the new Authenticator App. So it won't authenticate you.
You can't add this new app to your account as well, because you need to first get into your account in order to add it.
There are a few options available
- Do you still have your old device? That should work.
- Do you have the option to authenticate via other means like email?3. Can you contact your administrator / alternative administrator to reset your account?
- If you are the administrator, did you purchase from a reseller? Can the reseller use delegated admin to help you reset your account?5. If you are the only administrator, and there are no other means for you to get access, then you have to contact the Microsoft Global Support phone numbers
https://support.microsoft.com/en-us/topic/customer-service-phone-numbers-c0389ade-5640-e588-8b0e-28de8afeb3f2
- These phone numbers have Interactive Voice Response agent (IVR). Due to phone connection quality, and also your accent, some people have feedback that they have difficulty talking to a person. So using a good phone line, speaking slowly and clearly, might be an important factor.
- Others have feedback that following this script might be helpful
IVR: What kind of problem are you concerned about?
You: Authenticator.
IVR: What kind of product do you use?
You: Office 365 for business.
IVR confirmation: education or company account?
You: For companies or For education
IVR: Are you an administrator?
You: Yes.
IVR: Do you have the other administrator in your organization?
You: No.
IVR: Do you need a... Service request?
You: Yes
Hope this helps