Configuring Single Logout with SAML

I have been unable to achieve Single Logout with my SAML configuration. When logged out of the IdP, the Appian session continues to be valid.
It works when done the other way round (i.e.: When I logout from Appian, the session in the IdP is ended). I am using Keycloak as my IdP.

I got the from the knowledge base at community.appian.com/.../kb-1153-saml-authentication-faq

"I have noticed that logging out of my IdP does not end my session in Appian. How can I configure this to end my session in Appian too?

When logging out of the IdP, it is necessary for the IdP to then send a valid logout request to Appian. Once Appian receives a valid logout request from the IdP, Appian will terminate the user's session."

From what I understand of KB-1153, the logut request is to be sent to https://<my Appian app>/suite/saml/LogoutConsumer. I have already done this configuration at the Keycloak end.

Any suggestion on what else I could try on Appian's end or the IdP's end to get Single Logout working?