A call to SSPI Faild : Error

hi,

I have created ServicesGroup → salesOrderServiceGroup1.

I am then opening Vs2010 and in a project i am calling that service in Service References.

I have designed the form with 2 textbox and 1 button. on click of button i have written the code.

when i execute the code in Vs2010 i am getting this error

SecurtiyNegotiationException was unhandled

A call to SSPI failed, see inner exception.

I am new in Ax, I am not able to understand why this error is coming and how can I solve this error.

Can any one help me in this. Thanks in advance for your help

Himanshu