I have a web application that connects to the Dynamics 365 Event Management API that is being built to allow logged-in users to register for events (and also cancel these registrations).

1. The web application uses Azure AD B2C for user authentication.
2. I’ve also created a web application token in my Dynamics environment for use with the Event Management API.

When I send a request to the Event Management API for canceling a user’s registration for am event using the endpoint
POST/users/authenticated/registrations/{eventRegistrationId}/cancel ,

I get back a 200 OK response, but the response body contains false, which indicates that the cancel request was not successful. I do not get any information pertinent to why the request failed.

I can confirm that the Authorization header for the user is also being sent as part of the request.

Any clues? Is there a way I could get the actual reason why the request fails, like enabling some additional logging in the response?