Can’t login to Office365 using Single Sign-On if UPN uses sub-domain

Scenario:

You have federated your domain with Office 365 to provide Single Sign-On for your users

Problem

Some or all of your users cannot sign into Office 365.  Users are presented with the following error:

SSO1

Looking closer at the description you see the following:

AADSTS50107: Requested federation realm object ‘http://subdomain.domain.com/adfs/services/trust/’ does not exist. read more