With Multi-Factor Authentication (MFA), you can significantly increase the security of your Microsoft 365 accounts. In addition to entering your login details, you will then need to authenticate yourself further, e.g. through an app or your phone.


Alternative terms for multi-factor authentication include MFA, two-factor authentication, or two-step verification.

Setting Up Multi-factor Authentication

To set up the multi-factor authentication for the first time, you will need to activate it:

  • Call IONOS Customer Service.
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  • Mention each email address for which multi-factor authentication should be activated. Note that the setup may take some time. Once the setup is complete, the Additional Security Check dialog appears after your normal Microsoft 365 login.
  • Select your additional verification method. The verification method you select will be applied from your next login.

Resetting the Multi-Factor Authentication

To reset an activated multi-level authentication, e.g. because the stored telephone number is no longer reachable, contact IONOS Customer Service.

Note that a reset may take some time, especially on weekends and holidays.