REST call in FBA WebApp returns error 401 unauthorized

Question

Update:
I found out that this is happening only in a webapplication where FBA is activated. How can this be related? As soon as I deactivate FBA, 401 is gone.
Hello,
I'm trying to do a very basic REST call from a Console application to my SharePoint 2013. As I understand, that might be already the problem, as I'm having a hard time to authenticate my console app using oauth (which is necessary if I'm not mistaken). If
I use default credentials, everything is working just fine. If not, I receive an error 401 unauthorized. This is my code when I try to use very basic authentication using CredentialCache:
var req = (HttpWebRequest)HttpWebRequest.Create("http://{serverurl}/_api/lists/");
req.Method = WebRequestMethods.Http.Get;
var ccache = new CredentialCache();
ccache.Add(new Uri("http://{serverurl}/"), "Basic", new NetworkCredential("{username}", "{password}", "{domain}"));
req.Credentials = ccache;
req.Headers.Add("X-FORMS_BASED_AUTH_ACCEPTED", "f");
var response = (HttpWebResponse)req.GetResponse();
I've only replaced some irrelevant data with some placeholders. Thanks for your help and any clearification
Regards Andreas MCPD SharePoint 2010. Please remember to mark your question as "answered"/"Vote helpful" if this solves/helps your problem.

Answer 1

Hey Amr,
thanks for your feedback. Let me write down some more facts about my environment so we might be able to track down what's going wrong:
- Virtual PC using Windows Server 2012
- SharePoint 2013 with September CU
- Compatibility Level 15 Webapplication using Default "Claims Based Authentication" with form based authentication activated
- Visual Studio 2013 Console Application .NET 4.5 x64 Build Target
Writing down what my base configuration is seems to have brought light into the dark. As soon as I deactivated FBA authentication I was able to execute the request without any problems. So now I know what I have to look for. Thank you!
Regards Andreas MCPD SharePoint 2010. Please remember to mark your question as "answered"/"Vote helpful" if this solves/helps your problem.