The user receives an AADSTS50107 error when attempting to sign in to Office 365. The full error message reads:

AADSTS50107: The requested federation realm object 'subdomain.domain.com:exk123456789' does not exist

• Office 365
• Office 365 Federation with Child Domains
• Single Sign-On (SSO)
• Okta Classic Engine
• Okta Identity Engine (OIE)

The issue occurs for customers with a federation with child domains that was set up before the recent platform update. See Okta Classic Engine release notes (Production) for reference.

The update implemented a fix, but the configuration requires a refresh to apply the changes.

Perform the following steps to resolve the issue:

1. In the Okta Admin Dashboard, navigate to Applications > Applications > Office 365.
2. Select the Sign On tab.
3. Click Edit.
4. Click Fetch and select.
5. Click Select without modifying any settings.
6. Click Save at the bottom.