Can you check the requests performed in the browser? Are the scripts requested via webresources from your application, or are they requested from the cloud (e.g., something like http://aspnet-scripts.telerikstatic.com/ajaxz/2013.3.1324/Common/Core.js)?
In case they are requested from the cloud and your network administrators have blocked access to them, the requests will not return scripts, but an error, so our controls would not be able to function. You will need to disabled the CDN in this case: http://www.telerik.com/help/aspnet-ajax/scriptmanager-cdn-support.html
If webresource requests fail, it is possible that the application itself has permissions/user roles implemneted and the user does not have access to the webresource handler. In this case you should add a location element to the web.config to allow access. You can find an example here: http://www.telerik.com/help/aspnet-ajax/introduction-troubleshooting.html
, just find the word "location" on the page.
If you are still having issues with webresources examine this article: http://www.telerik.com/help/aspnet-ajax/introduction-web-resources-troubleshooting.html
. An alternative would be setting up your custom CDN on your internal servers where access to the files is allowed: http://www.telerik.com/help/aspnet-ajax/cdn-custom-provider.html
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