Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hello!
I'm Yasllame. I'm here to help and clarify.
This behavior is expected. Even when you use a passkey/biometrics to sign in to your Microsoft account, the account still has a password associated in the background. Some security actions—such as adding or changing a phone number—require password confirmation and do not accept a passkey as a substitute.
What you can do:
Create or reset a password for the account
Go to: https://account.microsoft.com/security
Go to Advanced security
Choose Change password or Create password
Set a password (it can be used only for verifications if you prefer to continue using the passkey daily)
After setting the password:
Return to the process of adding the phone number
When prompted, enter the newly created password
Important to know:
The passkey will continue to function normally after this.
The password does not disable biometric authentication.
This requirement is a security measure documented by Microsoft for sensitive account changes.
If, after setting the password, the problem persists, the next step would be to try the process in a different browser or contact Microsoft support, as public forums do not have access to accounts or authentication data.
I hope this information has been helpful! If you need anything else, I'm here.
Sincerely,