A Microsoft app for iOS and Android devices that enables authentication with two-factor verification, phone sign-in, and code generation
While the backup can be restored to a new phone, the new phone is not an authorized device. For each account you must authorize the new phone. Typically you would use your old phone or alternate MFA for that account. If this can not be done, you will need to preform an account reset (forgot password) for each account.
If you have the old phone, then on the new phone click each account and authorize by approving on the old phone.
Note: if you can not restore the backup, just create on the new phone, and authorize from the old phone. I setup my iPad is an alternative authentication device and also setup an alternative MFA method for each account. This way a lost phone is recoverable.