I'm trying to build a custom app that uses Azure AD B2B to log users that are defined in multiple SAML Identity Providers.
I was able to add an Okta Idp and a guest user for that Idp. The user got the email and accepted the invitation - he was sent back to okta for signing in and everything seems to have worked ok.
He was later added to our custom app, but when he tries to sign in he gets an error message saying "This username may be incorrect. Make sure you typed it correctly. Otherwise, contact your admin."
Any idea what the issue might be?