What is a SAML2 logout failure?

When using SAML2 apps with the SurePassID SAML2 IdP, the logout target is https://<SP_IDP_FQDN>/SAML/Logout.aspx.

For SAML2 applications that allow you to specify a logout URL, use the following pathing:

https://SP_IDP_FQDN/SAML/Logout.aspx

For example, to logout from the sandbox SAML2 IdP:

https://saml2-sandbox.surepassid.com/SAML/logout.aspx

Using the above will result in a "clean" logout from the system with the appropriate message displayed upon doing so.