Your SAML certification hostname and Tableau Server hostname should be the same - it's one of the core requirements for using SAML with Tableau Server, I'm surprised Tableau Desktp can connect with this configuration. Is there a reason the two do not match? Can they be made to match?
I am having the same issue.
We have SAML authentication setup with certificate A, but we don't have any other certificates associated with our server configuration. Do i need to add the certificate somewhere else beside the tableau server/ssl/ folder?