Hello Miguel,
As I can see from the provided liveUrl, the Telerik resources are not properly loaded. This might be caused by the login form and by the approach used for the prevention from unauthorized users. Please try to set a
<location> section to the application configuration file to allow access to
Telerik.Web.UI.WebResource.axd to all users, as follows :
In addition, refer to the following documentation article, demonstrating this solution and several other causes of such issues along with their solutions:
http://www.telerik.com/help/aspnet-ajax/introduction-troubleshooting.html
Regards,
Nencho
Telerik
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.