I did set printTask.ProxyURL = Proxy_URL, also with this proxy, I can call the Map Service and display it on my map control with no problem but cannot print with the MapService?? Please help on this!!
Ok, you are right. The problem is this proxy. I am using a proxy - for ArcGIS API for Silverlight server-side ASP.NET proxy for IIS, but not a proxy server. I don't know what i am missing.???
Yes, I had added parameter username and password in your proxy file (proxy.config). That why the map service is successfully to add to my map through this proxy. I know my proxy is configured correctly.