Access Denied Error from SoaupUI for REST web service

hello,

I am trying to invoice sample REST web service from SOAPUI then I am getting error 

If I put Proxy settings to "None"

"Error Code: 403 Forbidden. Forefront TMG denied the specified Uniform Resource Locator (URL). (12202)"

If I change Proxy settings to "Automatic"

Then I am getting "Invalid Credentials" - even I provide correct credentials.

I am using SOAPUI 5.2.1.

Can anybody let me know how to resolve this error?

if the same url I am executing from browser then It is working fine, only with SOAPUI I am getting error.

Regards,

Khaja.