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Error: '~/Telerik.Web.UI.WebResource.axd' is missing in web.config. RadStyleSheetManager requires a HttpHandler registration in web.config.

Description

Getting the below error:

~/Telerik.Web.UI.WebResource.axd' is missing in web.config. RadStyleSheetManager requires a HttpHandler registration in web.config. Please, use the control Smart Tag to add the handler automatically, or see the help for more information: Controls > RadStyleSheetManager

Solution

Below are the common troubleshooting steps to solve this error:

  • Remove RadCompression (if enabled) as it is deprecated.

  • Try setting the EnableHandlerDetection property to false for the RadStyleSheetManager and the RadScriptManager as it may be that simply the application pool user is not allowed to read the web.config and thus the check fails even if the handler will actually work:

     <telerik:RadScriptManager ID="ScriptManager1" runat="server" EnableHandlerDetection="false">
    </telerik:RadScriptManager>
    <telerik:RadStyleSheetManager runat="server" ID="RadStyleSheetManager1" EnableHandlerDetection="false">
    </telerik:RadStyleSheetManager>
    
  • Review the following article in case the webresource requests themselves break, the most common reason is that authentication blocks them and you'd need to add elements to allow it. Link: Web Resources Troubleshooting

    Example:

    <configuration>
    ...
    <location path="Telerik.Web.UI.WebResource.axd">
    <system.web>
    <authorization>
    <allow users="*"/>
    </authorization>
    </system.web>
    </location>
    ...
    </configuration>
    
  • Check for any nested web.config files

  • Examine other support cases on the topic:

See Also

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