If you see this error in SharePoint 2013 make sure that the settings in your environment match the settings below.
- Make sure that Forms Authentication is disabled on application level. The IIS settings in this case should look like the following:
Disable ClaimsBasedAuthentication as shown in the code snippet below in PowerShell.
$webApp = Get-SPWebApplication "http://webapplicationurl" $webApp.UseClaimsAuthentication = 0; $webApp.Update()
After the code executes then Authentication Type should be set to Windows. You can verify this by opening Central Administration -> Application Management -> Manage web applications select the Sharepoint-80 main application and click on Authentication Providers. It should say Default - Windows as shown below:
Ensure that the Negotiate (Kerberos) option is selected for Integrated Windows Authentication.
Check the web.config file in (C:\inetpub\wwwroot\wss\VirtualDirectories\80) and make sure it has the following settings there. Note that authentication mode is set to Windows.
<customErrors mode="Off" />
<httpRuntime maxRequestLength="51200" requestValidationMode="2.0" />
<forms loginUrl="/_login/default.aspx" />
<identity impersonate="true" />
<allow users="*" />
. . .
Ensure that the correct version of Telerik assemblies is referenced in the web.config
Make sure that the IIS worker processes have full access to the GridWebPartDesigner.aspx and gridbindingservice.svc files.
- Restart IIS and browser and try loading the designer again
Below you can see suggestions that can help resolve other common issues with the WebPart Designer.
Use the .msi installer to install the controls. This way any additional resources that are required by the designer will be added automatically
If you are using Internet Explorer, ensure that Compatibility Mode is Disabled
Ensure that only one version of the Telerik.Web.UI assembly is referenced throughout the whole Sharepoint application. Also in GAC, IIS Sharepoint Bin(C:\inetpub\wwwroot\wss\VirtualDirectories\80) folder and the web.config
If you are adding RadGrid or RadListView controls open the C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\TEMPLATE\LAYOUTS\Telerik.Ajax.SharePoint folder and ensure that the correct version is referenced in the GridWebPartDesigner.aspx / ListViewWebPartDesigner.aspx files
Open the C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\ISAPI\Telerik.Ajax.SharePoint folder and ensure that the correct version of the controls is referenced in the gridbindingservice.svc file
Check the vti_bin folder in the Sharepoint IIS web site and confirm that it has anonymous authentication enabled
After the designer is opened check the browser console and the Sharepoint logs for any errors
Inspect the HTML content of the designer and ensure that all inner controls are loaded as expected
Examine the files in the C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\TEMPLATE\LAYOUTS\Telerik.Ajax.SharePoint folder and ensure that the correct version of the Telerik.Web.UI.dll is registered
Ensure that the Sharepoint administrator and the IIS processes have permission to access the SPRadGridWebPartDesignerService.asmx file located in the C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\ISAPI folder
Enable Network traffic capturing in the browser console and check it the requests made to the server are successful when opening the designer
Disable Forms Authentication in the IIS settings of the current Sharepoint site
If you are seeing the following error make sure that Telerik.Web.UI.dll is present only in one of the folders (either GAC or the Bin folder)