We have an on-premise installation of sharepoint 2013 with an app domain configured.
So far so good, I can create a Sharepoint Provider hosted app, where the Web-project runs on a local IIS. The sharepoint app part contains a list definition with a remote evenet reciever that is contained inside the web-project.
I did register the app using appregnew.aspx page.
Now everytime I add an item to the list, the webservices gets called correctly. However I can't load the clientContext using
using (ClientContext clientContext = TokenHelper.CreateRemoteEventReceiverClientContext(properties)) { if (clientContext != null) { clientContext.Load(clientContext.Web); clientContext.ExecuteQuery(); if (properties.EventType == SPRemoteEventType.ItemAdded) { } } } When I check the Error-Properties of the variable "properties", I get following message: 
I tried all different kinds of app registrations on the page appregnew.aspx. Also I added the endpoint adress to <RemoteEndpoints> tag inside the AppManifest.xml
Can anybody help me out here? This error starts to drive me crazy after hours of debugging...