Handling HTTP Error 500
Your Web app will call MediaKeySession.Update to process the license acquisition response when it receives a success code for the HTTP license request from the license server. If the request is successful, an HTTP 200 code is returned from the license server.
In most cases if an HTTP error code is returned from the license server, the Web app must handle the error and stop. However, if the error code returned from the license server processing the license acquisition challenge is HTTP 500, some additional response data is also returned with the error.
In this case, your Web app can call MediaKeySession.Update(responseData). This method will return a more meaningful error code back to your Web app.