- Within IIS on the server hosting your Reporting Services website, right click the ReportServer virtual directory and select Properties…
- On the Virtual Directory tab select the Configuration… button
- On the Mappings tab of the Application Configuration dialog take a look at the box containing Wildcard application maps (order of implementation).
- Mine was missing the c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\aspnet_isapi.dll entry. I also compared this setting against a similar server which had a working Report Server.
- I add the c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\aspnet_isapi.dll entry to the list and then restarted IIS.
Thankfully, this was a successful solution and my access to the Report Server was restored. My reports view in Microsoft CRM had not quite been resolved because I was being shown a different error – Reports.config has invalid schema, and could not be loaded. This issue is discussed in this blog entry.