0x80100005: Unable to obtain credential

hi, 

I am trying to use Azure Active Directory to authenticate a user within a console app. 

I've performed the following steps:

1. Went to the Azure Active Directory preview portal and created a new tenant. 

2. Verified that the endpoint with the tenat excists. 

3. Used Powershell to create a new service principal within the tenant:

DisplayName           : Central
ServicePrincipalNames : {Central/localhost, -57f8-4dab-b967-492
                        91f3a750e}
ObjectId              : 387a9042-7ad5--4967d23786c1
AppPrincipalId        : 6638c788-57f8--49291f3a7501
TrustedForDelegation  : False
AccountEnabled        : True
Addresses             : {}
KeyType               : Symmetric
KeyId                 : 
StartDate             : 10/1/2012 7:00:00 AM
EndDate               : 10/1/2015 7:00:00 AM
Usage                 : Verify

Created a new console app

4. Added the azure authentication library

5. Tried the following lines of code

var _authContext = new AuthenticationContext("https://accounts.accesscontrol.windows.net/p???.onmicrosoft.com");


            UsernamePasswordCredential c = new UsernamePasswordCredential("p??.onmicrosoft.com", "1", "2");

            AssertionCredential z = _authContext.AcquireToken("urn:NonInteractiveAuthentication" ,c);

And I get the error AAL 0x80100005: Unable to obtain credential

Anybody any suggestions ?