Two-step verification: The standard verification method, where one of the factors is your password. You can use the Authenticator app in multiple ways: Two-step verification uses a second step like your phone to make it harder for other people to break in to your account. Two-step verification helps you to use your accounts more securely because passwords can be forgotten, stolen, or compromised. The Microsoft Authenticator app helps you sign in to your accounts when you're using two-step verification.

Also, you can get more info about what to do when you receive the “ That Microsoft account doesn't exist” message when you try to sign in to your Microsoft account. If you're having issues signing in to your account, see When you can't sign in to your Microsoft account for help. If you're an administrator, you can find more information about how to set up and manage your Azure Active Directory (Azure AD) authentication environment in the administrative documentation for Azure Active Directory.

Ms authenticator