I created a new Project for Sharepoint 2013 Apps in the Visual Studio 12. I choosed autohosted and added the link to my SP Web Home Site. I also added:
<AppPermissionRequest Scope="http://sharepoint/content/sitecollection/web" Right="Read" />
in the AppManifest.
So why is the method
TokenHelper.GetContextTokenFromRequet in the Default.aspx.cs always returning null?