Symptoms
SharePoint 2013 workflow does not start on "Item Added", but starting the process manually does work.
Diagnoses
Accessing the http or https://pK2Server]:vWorkspacePort]/SP15EventService/RemoteEventService.svc URL from the K2 or SharePoint server results in a 404.17 - Not Found error. No errors are in the HostServer log, there does not appear to be any activity on the K2 server for that process.
As per K2 documentation: "When using Windows Server 2012 / IIS 8, you will be unable to trigger Workflows from SharePoint Events unless the HTTP Activation feature is installed."
Consequently first thing is to check/confirm in this scenario is whether you have HTTP Activation feature installed and if not add it (Start > Administrative Tools > Server Manager then to Features and select Add Features to add the HTTP Activation).
When HTTP Activation feature is not installed you are going to get "HTTP Error 404.17 - Not Found" upon attempt to access K2 Web Service URL. To confirm this you can check default K2 Web Service URL field value in your environment library. Take this URL and append it with the following affix:
/SP15EventService/RemoteEventService.svc
You should be able to browse to this URL if everything is configured correctly. In case you getting HTTP Error 404.17 it means that HTTP Activation feature is not installed. Note: it has to be installed for both versions of .NET (.NET 3.5 & 4.5 for Windows Server 2012).
Resolution
The 404.17 error is caused by the HTTP Activation feature not being installed for both .NET 3.5 and .NET 4.5. Once these features are installed, the service for the event receivers is accessible. This resolves the issue in many cases.
