Hi, I am trying to write a simple application that performs Kerberos authentication (no mutual authentication for now). The operating system is Windows server 2003, standard edition. I have setup Active directory and created an SPN using setspn tool. AcquireCredentialsHandle returns SEC_E_OK both on client and on server. InitializeSecurityContext on client side returns SEC_E_OK. AcceptSecurityContext on server side returns SEC_E_LOGON_DENIED. I am sure there's nothing wrong in my code since the same behaviour I see when using the sample application from the following MSDN article: http://msdn.microsoft.com/en-us/magazine/dvdarchive/bb985043.aspx So I guess there is something wrong in my setup. But I can't find out what. Maybe I have missed something in SPN setup? Any help is appreciated. Regards, David.