I am working on adding a custom SAML 2.0 identity provider (Okta) to use with my B2C tenant. I have configured it and it works great when I initiate the login from my application. However, when I initiate the login from the identity provider (Okta) it fails to login. The first attempt I received this error from B2C: "does not specify first step or the first step is not a claims exchange". As a result of this error, I removed the extra claims providers from the custom policy so the ClaimsExchange was the first journey step and then I received this error, "Specified method is not supported.".
Is this scenario supported? If so, what changes to the custom policies need to be done to support it?