What to Do If a Device Used for Multi-Factor Authentication (MFA) is Lost or Broken.

Q. What to do if a device used for multi-factor authentication (MFA) is lost or broken?

A. If the smartphone used for MFA is lost or damaged, take the following actions:

【Device Malfunction】

■If phone number authentication is already registered:

1. Please sign in to the Microsoft 365 Copilot Home as instructed in the article below.

   Authentication method using a phone number.

2. Please reconfigure the Microsoft Authenticator app according to the instructions in the article below.

   How to reconfigure the Microsoft Authenticator app.

   After adding a new authentication app, please remove "Microsoft Authenticator" from your registered sign-in methods.

■If phone number authentication is not registered:

  Administrator action required: Clearing multi-factor authentication registration.

  Please submit your request using the following inquiry form:

  ・THERS Account Contact Form

【Loss of smartphone】

  Administrator action required: Clearing multi-factor authentication registration.

  Please submit your request using the following inquiry form:

  ・THERS Account Contact Form