Recently, O365 started prompting users in my organization during sign-in to add an alternative (Authentication verification) email address. This is not an option we turned on, nor is it an option I wanted to be enabled. If the user needs help resetting their password or having issues signing in, our policy is for them to contact our helpdesk.
To remove this, you will need to go into your admin portal. Then go into Azure Active Directory, then USERS, then REGISTRATION. Change the option, “Require user to register when signing in“, to NO.
Now your users will no longer get prompted to enter an alternative email address for authentication verification. Our policy is that the IT department should be contacted.