Which two considerations should the architect review to troubleshoot the issue?

Universal Containers (UC) has implemented SAML-based SSO solution for use with their multi-org Salesforce implementation, utilizing one of the the orgs as the Identity Provider. One user is reporting that they can log in to the Identity Provider org but get a generic SAML error message when accessing the other orgs .

Which two considerations should the architect review to troubleshoot the issue? Choose 2 answers
A . The Federation ID must be a valid Salesforce Username
B . The Federation ID must is case sensitive
C . The Federation ID must be in the form of an email address.
D . The Federation ID must be populated on the user record.

Answer: B,D