We have a sharepoint 2010 application, used to support classic authentication mode SSO. The behavior of the application in SSO senario is that, after user logon to sharepoint, user get redirected to the application instead of application's own logon page. However, if create the application using claim based authentication, SSO stops working.
What I have tried: use C2WTS to get upn from claims and impersonate it before call logon function as normal. However the application still fail. after steped into the backend logon code, found that its failing at AcquireCredentialsHandle() SSPI function, with error code SEC_E_NO_CREDENTIALS. Anyone knows the possible cause?