I'm trying to use the print service that is included with ArcGIS Viewer for Silverlight, version 3.1.0.110.
I have started the print service on server (ArcGIS for Server version 10.2) but when I attempt to print from the webmap, I get the message "Print failed" with no further information.

This happens whether I use the default print service url in the tool's dialog (Task: Export Web Map Task ) or the path to our own server.

The print templates appear to load successfully from either server path but when I try to print it always fails with no information about the error. Any suggestions are greatly appreciated.