Sometimes, when trying to enable Okta Multi-Factor Authentication (MFA) from Microsoft Azure AD, the below error might be seen:

Please review the form to correct the following error(s):

UNEXPECTED_ERROR

Additionally, the System Logs will show the following error:

Could not validate your Office 365 credentials, received error: 400 AADSTS50126

• Microsoft Entra ID (formerly Microsoft Azure AD)
• Microsoft 365 (M365)
• Multi-Factor Authentication (MFA)

The Advanced API Access is not enabled.

To resolve the issue:

1. Navigate to the Sign On tab of the Okta Office 365 app.
2. Under Settings > API CREDENTIALS > Advanced API Access, select the checkbox for Allow administrator to consent for advanced API access.