Proxy Error: Error reading from remote server

[Ctrax]

I have a Telerik report with a SQL Data Source query that can take up to 10 minutes to run depending on the parameters selected and number of records returned.  When the report runs for over 6 minutes (approximately), it encounters the following error:

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /CustomReports/Telerik.ReportViewer.axd.

Reason: Error reading from remote server

If I refine my selection criteria so that it runs under that timeframe, it finishes successfully.  Does this error indicate that a timeout is occurring somewhere?  I confirmed that the timeout value on the data source is set to 3000 minutes, so that doesn't appear to be the issue.  

[Stef]

Hi Keith,

Please check how Telerik Reporting handlers are registered in the configuration file, try to use first remove and then add:

<system.web>
    <httpHandlers>
      <remove path="Telerik.ReportViewer.axd" verb="*"/>
      <add path="Telerik.ReportViewer.axd"
           verb="*"
           type="Telerik.ReportViewer.WebForms.HttpHandler, Telerik.ReportViewer.WebForms, Version=7.2.13.1105, Culture=neutral, PublicKeyToken=a9d7983dfcc261be"/>
    </httpHandlers>
......

Also check if the authorization rules allow access to the resources and inspect with Fiddler the requests during running the page with the viewer.

If you need further help, please post the Fiddler log files' details and the exception stack trace.

Regards,
Stef
Telerik