Configured Mirror Gateway to work with Okta and Office 365. After providing Okta credentials received the following error
Unlike other SaaS Office 365 requires an immutableID to be passed to as an Okta attribute instead of username.
Release : 1.0
To resolve this add an attribute to the Okta SAML response with the following information.
MIGNameID Unspecified user.office365_immutableid
You will need to type in user.office365_immutableid as it will not show up in the drop down.