Hi @Paul Levett , thank you for returning with your answer. Since you can't confirm your own answer, I'll repost it here for others to reference. Please select "Verify Answer" to do this.
The issue was resolved by:
- Going to Entra ID > Identity > All Users
- Change the UPN domain for each affected user to their onmicrosoft.com UPN and save to confirm the domain change
- Open Powershell and run this command:
set-msolUser -userprincipalname name@<domain name> -immutableID name@<domain name>
- Once the command has completed go back to Entra ID > Identity > All Users and change the affected users back to the federated domain.
All users can now access their Microsoft Services via Google Workspace.