I am currently facing an issue with the WCF services integration with K2 environment.

1. Implemented a logic in WCF for which it requires impersonation of client user credentials. WCF is exposed under WCF endpoint Service object. Service object instance is set to Imperosnation mode.

2. Unit testing of WCF code is fine. User credential are correctly passed. But when the service is hosted to IIS the data wasn't getting returned
   though (Service object for WCF Sensitive data is set on Impersonate).On further analysis found the below
   result:

   a. When I debug using service object tester tool, WCF gets the  user identity of client  (authentication type: NTLM).

   b. When the same smart object is called through the smartform the Service account identity is passed instead (authentication type: Kerberos).

I am wondering what is difference as in both cases same smart object is being used.  The WCF service Anonymous login is Disabled and Windows = Enabled.

Need some help from you as running bit out of ideas.