I'm trying to implement an OpenID provider with DotNetOpenAuth. I supply an OpenID url, and the consumer discovers my endpoint. I log into my provider, and the provider returns a Claimed Identifier and a Local Identifier to the consumer. But the consumer response has the following exception: The OpenID Provider issued an assertion for an Identifier whose discovery information did not match. Assertion endpoint info: ClaimedIdentifier: http://localhost/OpenIDUser.aspx/myuser ProviderLocalIdentifier: http://localhost/OpenIDUser.aspx/myuser ProviderEndpoint: http://localhost/OpenIDAuth.aspx OpenID version: 2.0 Service Type URIs: Discovered endpoint info: [] http://localhost/OpenIDAuth.aspx is my endpoint. http://localhost/OpenIDUser.aspx/myuser is my user identifier url, and I can browse to it successfully. It has a link to the endpoint in the header as follows: <link rel="openid.server" href="http://localhost/OpenIDAuth.aspx"></link> No matter what I try, the "Discovered endpoint info: []" part of the exception is always an empty array. Can anyone please help?