The status code returned by the service from your second screenshot
is 500. It is possible that something blocks the web service. Please check the service parameters that are passed. You can also try to get the service url ( with the parameters ) and paste it to the browser.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items