ms crm 2013 reports not working

Hi All,

I am getting below error while running custom reports from reporting services.

Also i have set spn for crm report as per this site....

support.microsoft.com/.../microsoft-dynamics-crm-2011-reports-created-by-report-wizard-may-fail

• An error has occurred during report processing. (rsProcessingAborted)
  • Query execution failed for dataset 'DSMain'. (rsErrorExecutingCommand)
    • Microsoft.Crm.CrmException: An unexpected error occurred. System.ServiceModel.Security.SecurityNegotiationException: A call to SSPI failed, see inner exception. System.Security.Authentication.AuthenticationException: A call to SSPI failed, see inner exception. System.ComponentModel.Win32Exception: The target principal name is incorrect
      • An unexpected error occurred.
        • A call to SSPI failed, see inner exception.
          • A call to SSPI failed, see inner exception.
            • The target principal name is incorrect