Well, that's strange since we tried this over and over again to make sure it works.
As far as the web.config file of the STS site is concerned, there is no need to add anything there (it should only have the <add key="(the address of your Sitefinity website)" value="(the key you created in Step 5b)"/> which is described here
and you have probably done this when setting up the configuration).
Is the name of your membership provider LdapUsers or it is changed? Perhaps, there is a mismatch in the configuration.
I would suggest the following approach:
Would you be so nice to give us the configuration settings related to Security in your Sitefinity site - some screenshots for example. Or you can create a test user for us and we'll log in your site and go through the settings.
Thank you very much for your patience and cooperation.
the Telerik team
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