I have a application that uses the SharePoint 2010 REST API. In the process of creating an Item there are multiple request done after each other:
1 Call:
Just run into the same problem.
Anyway, the 2nd request does not follow the same authentication procedure. Even if you initialize a new HttpClient object. I sniffed the HTTP traffic.
After the 1st request I am doing another with different credentials. This is also ending in a 401. I am really confused...
Seems the NTLM Handshake stucks at the 2nd of 6 steps http://www.innovation.ch/personal/ronald/ntlm.html
Edit: You may want to use the CSOM. http://social.msdn.microsoft.com/Forums/office/en-US/efd12f11-cdb3-4b28-a9e0-32bfab71a419/windows-phone-81-sdk-for-sharepoint-csom?forum=sharepointdevelopment