The error about the assertion consumer service URL can occur during SP-initiated SSO rather than SLO. The SAML authn request that's sent when you call SAMLServiceProvider.InitiateSSO includes your assertion consumer service URL. This URL is the <ServiceProvider> AssertionConsunerServiceUrl from your saml.config. Alternatively, there is a SAMLServiceProvider.InitiateSSO overload where you can specify this URL.
ADFS performs a check when processing the SAML authn request. The specified assertion consumer service URL must match one of the URLs configured for your relying party. If it doesn't, it logs the error you see and returns a SAML response with an error status.
When you call SAMLServiceProvider.ReceiveSSO, if the SAML response status isn't success we throw an exception.
Please check that you're not specifying the assertion consumer service URL as a parameter to SAMLServiceProvider.InitiateSSO.
Are you seeing an exception being thrown by SAMLServiceProvider.ReceiveSSO?
For SLO, ADFS requires that the SAML logout messages are signed.
Please update your saml.config to specify SignLogoutRequest="true" and SignLogoutResponse="true" for your <PartnerIdentityProvider>.
If there's still an issue, please enable SAML trace and send the generated log file as an email attachment to [email protected]
mentioning your forum post.https://www.componentspace.com/Forums/17/Enabing-SAML-Trace