Hello,
We are a service provider, and one of our customers is using MDCA, and using Entra ID to do SSO into our mobile app. We use Google Firebase Auth (aka Google Cloud Identity Platform) as our identity platform (similar to Auth0) to integrate multiple OIDC providers (Microsoft, Google, Apple).
Back in December this authentication flow worked perfectly, but something appears to have changed recently with the behavior of the MDCA proxy. Nothing has changed on our end or the customer's MDCA configuration.
Now it appears that, after successful Entra auth, the redirect to our Firebase authentication domain ([redacted].firebaseapp.com) is loaded as [redacted].firebaseapp.com.mcas.ms and the user sees a Firebase Auth error screen. I am guessing that Firebase Auth is somehow incompatible with the MDCA proxy, and cannot handle the unexpected the domain change. Unfortunately, because it is a third-party service, we don't have the ability to fix it.
@Keith_Fleming I saw your comment on another recent post that "there have been some recent changes to the behavior" related to the MDCA proxy. Could a recent change be the cause of this issue? Could you suggest any paths forward? We were about to launch with this customer, when the issue popped up.
Thank you so much for any help.
