Have you disabled the anonymous access through the web.config file:
| <authentication mode="Forms">
| <forms name=".ASPNET" loginUrl="~/sitefinity/login.aspx" protection="All" timeout="1440" path="/" />
| <deny users="?" />
You could also have been disabled the access for a certain role. Please check these settings, and let us know if this is related to the issue you are experiencing.
the Telerik team
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