Phone Factor - "mfa-phone-challenge" vs. "mfa-sms-challenge"

Last Updated: Feb 20, 2026

Overview

After enrolling in MFA using the phone factor, on subsequent logins, some users will see the mfa-phone-challenge, while others will see the mfa-sms-challenge when prompted for MFA. This article explains why they see different prompts.

Applies To

Multifactor Authentication
Phone factor
Phone Challange vs. SMS Challange

Solution

When users first enroll in MFA using the phone factor, they see the mfa-phone-enrollment screen.

If they choose to enroll using a Voice call first, on subsequent logins, they will see the mfa-phone-challenge screen, giving them the option to choose between sms and a call to deliver the code.
If the user chooses to enroll using a Text message first, on subsequent logins, they will see the mfa-sms-challenge screen, with a link to "Get a call" if they prefer so.

Each screen is described in this document. Please check it out for further details.