When a user logs in to Zivver with single sign-on (SSO) in the Outlook Web App (OWA) add-in or in the new Outlook add-in, the user is asked for multi-factor authentication (MFA) again and again. The login never completes.

Cause

Some Conditional Access policies in Entra ID trigger a new MFA challenge during the sign-in. The add-in shows the sign-in page in an embedded browser frame. This frame does not fully support the redirect flow that Conditional Access requires, so the user cannot complete the MFA challenge correctly and the challenge starts over.

Solution

1. Ask the user to open the Zivver WebApp or webmail in a full browser window.
   The user must not use the add-in for this step.
2. Ask the user to log in with SSO and complete the MFA challenge.
3. Ask the user to return to the add-in.
   The add-in picks up the existing session.

The problem persists

Does the login loop also occur in a full browser window? Then a Conditional Access policy in your organization probably blocks the sign-in. Review the Conditional Access policies in Entra ID:

1. Open the Conditional Access policies in Entra ID.
2. Find the policies that apply to the affected users and require MFA.
3. Add an exception to the policy for the sign-in context of the add-in.
4. Ask the user to log in to Zivver with SSO again.

For more background, see Microsoft’s documentation on Conditional Access.

Does the user see a Zivver password prompt after logging in, instead of repeated MFA prompts? See Single Sign-On - Troubleshooting login problems with Entra ID.