Summary

This article addresses a situation where Exchange Online mailbox backups failed with the error code EUAUTH, caused by Microsoft Entra ID (formerly Azure AD) enforcing Multi-Factor Authentication (MFA) for the administrator account used in the Druva app configuration.

Issue

Multiple Exchange mailbox backups were failing. Upon investigation in the Druva inSync Console, Exchange mailbox backups were observed to be failing with:

· Error Code: EUAUTH

· Detailed Error (from audit logs): AADSTS50076: Due to a configuration change made by your administrator, or because you moved to a new location, you must use multi-factor authentication to access.

Root Cause

The error AADSTS50076 is generated by Microsoft Entra ID and indicates that MFA is now required for the account used to authorize Druva’s access to Microsoft 365 services. This was not caused by any change in Druva, but rather :

A new or updated MFA policy, Security Defaults, or Conditional Access policy in Microsoft Entra ID.
Login attempts from new or untrusted locations trigger MFA.

Impact

Exchange Online backups are failing authentication.

Resolution: Reconfigure the Microsoft 365 App in Druva

Pre-Requisites

Access to the Druva Cloud Admin Console.
A Microsoft 365 Global Administrator account that can complete MFA.
Ensure your browser allows pop-ups.

Steps to Reconfigure the App

1. Log in to Druva Console

Visit: https://login.druva.com

2. Navigate to M365 Configuration

- Click Microsoft 365 from the left menu.

- Go to the Overview tab, then click Manage Apps.

3. Reinstall the App

- Locate the Exchange Online configuration.

- Click the ⋮ (three-dot menu) next to it.

- Select Reinstall App.

4. Sign in with Global Administrator Account

- You’ll be redirected to Microsoft’s login page.

- Log in with the Global Admin account used previously or a new one.

- Complete the MFA challenge, as required.

5. Grant Permissions

- Accept the required permissions for Druva to access your Microsoft 365 services.

- After successful authentication, you’ll return to the Druva console.

6. Verify Backup Functionality

- Trigger a manual backup for one or more affected users.

- Review the backup status in Reports > Backup Activity.

Recommendations to Prevent Recurrence

Use a dedicated service account for integration and exclude it from MFA using a Conditional Access Policy, if organizational policy permits.
If there are any changes in the MFA policy, you must reconfigure the app using the privileged account