In order to diagnose the issue and provide you with a solution I need to ask you a few questions. First of all did you make any changes before the error appears? Did you add something to it? Also did you use claims-based authentication of you use forms authentication?
Additionally, if you try to access the backend page like the URL bellow you will receive an error :
The error you are getting is a known issue, which is reproduced only on IIS6, but not on IIS7+.
However, it goes away when you add a slash to it:
We have logged the issue in PITS
, for which you can vote. You can also track its status. A workaround was proposed in the forum thread regarding the issue:
If you want to use IIS7 you have to switch to claim-based authentication. Here
you can find additional information about switching to this authentication.
All the best,
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items