SOLVED AADSTS50107 : Requested federation realm object "user10@abc.com" does not exist

You might encounter this error while deploy an Windows Autopilot Deployment for Hybrid Domain Join. Before that, make sure the pre-requisite for Autopilot Deployment is configured successfully. Here I share the main thing to check before deploy.

Device 

1)Windows 10 1809 version

2)Have an internet access connection

3)Have an access to local AD.

Intune

1)Device registered and grouped

2)Assigned deployment profile to the group of autopilot.

3)Assigned Domain Join Profile

4)Add Intune Connector and make sure to stay active

Azure AD 

1)Assigned EMS license to the user

Azure AD Connect

1)Successfully synced

2)1.1.89 version or later and configured as Hybrid Domain Join.

Intune Connector

1)Installed to Windows Server 2016

2)Have an access to internet and local AD.

3)Have a right to local AD to add computer object to local AD.

For this error, after checked on pre-requisite for Windows Autopilot deployment on AD environment. My situation is, currently I set  StaffID as User Principal Name (UPN). For Intune requirement might need email address for login credential. So, AD must change the UPN  to email address instead of StaffID. After change it, user can login to portal.manage.microsoft.com and register the device to Intune Company Portal.