Could not retrieve a valid windows identity for NTName='domain\username', UPN='username@domain.com'. UPN is required when Kerberos constrained delegation is used.

Hi,

We are displaying some wiki pages through web part.

Once user edits the page and clicks on save which is on the ribbon.

It is showing as unexpected error and displaying the message in the logs as below.

Here is there is no external authentication,only thing is 

We are validating the user details from the SQL DB for the permission.

Of course i saw the below article,but at the same time i am worried that

If i change the web config as specified it may loose the connectivity with DB.

Please help me out in resolving the same.

http://online.appdev.com/edge/blogs/doug_ware/archive/2011/04/16/beware-kb979917.aspx

Error

SPSecurityContext.WindowsIdentity: Could not retrieve a valid windows identity for NTName='domain\username', UPN='username@domain.com'. UPN is required when Kerberos constrained delegation is used. 

Exception: System.ServiceModel.EndpointNotFoundException: There was no endpoint listening at net.pipe://localhost/s4u/022694f3-9fbd-422b-b4b2-312e25dae2a2 that could accept the message. 

This is often caused by an incorrect address or SOAP action. See InnerException, if present, for more details. ---> System.IO.PipeException: The pipe endpoint 'net.pipe://localhost/s4u/022694f3-9fbd-422b-b4b2-312e25dae2a2' could not be found on your local machine.      --- End of inner exception stack trace ---    Server stack trace:      at System.ServiceModel.Channels.PipeConnectionInitiator.GetPipeName(Uri...    df2ecbcf-0523-4f8d-af18-0655147215f3

Regards,

Sudheer

Thanks & Regards, Sudheer