Windows Notifications Service: 401 Invalid Token when trying to create a Toast notification in PHP

Question

I have been trying to send a Toast notification to a simulator. I created the Windows Phone 8.1 app and Associated it with the app in the store. Afterwards I managed to get the

Answer 1

I found the solution.

The client_id that you have to send to request the token isn't the Client ID of your app. Instead of sending the Client ID you have to send the Package SID. Very confusing.