Whenever a PCA user in Unity Connection 7.x tries to hear inbox, he is getting the following error
MMApplet.Play: Quickplay cannot proceed due to a failure to obtain the stream identifier.
When press OK then we get the following
Error playing stream - waitForResource
The above situation only happens when the user use the URL which points to both servers in the cluster. If he logs in to the server directly, there is no error and could hear the message properly. This leads me to believe that there is some issue at the unity connection cluster level (may be certificate issue or some thing similar)