Silverlight + WCF common error debugging methods

1.404 Not Found

A. Check to see if the server has clientaccesspolicy.xml files. Examples of content are as follows:

<?xml version="1.0" encoding="utf-8" ?>
<access- policy>
<cross-domain-access>
<policy>
<allow-from http-request-headers="*">
<domain uri="*"/>
</allow-from>
<grant- to>
<resource path="/" include- subpaths="true"/>
</grant-to>
</policy>
</cross-domain-access>
</access-policy>

B. There may also be other reasons why you can use the HTTP listener to view the contents of the response and see the exception information.

2. The call to WCF was found to be missing and null.

Reason: The client agent is not synchronized, update the service reference.