Q. Why do I get this error sometimes when I log out of Canvas?

You will see this message when your Shibboleth (authentication via your Oxford single signon – SSO) session has ended, but your Canvas session is still active. Effectively, Canvas hands-off the logging in/out process to the central University authentication (IdP) system.

Canvas and the IdP have different session timeouts, with the IdP timeout being shorter than the Canvas one. Basically, when a session has timed out, it effectively means the user is no longer logged in to that system.

If both sessions are active, then clicking ‘Logout’ in Canvas will terminate your Canvas session, then tell the IdP to terminate your session there too. This will all work without error; however, if your IdP session has already ended (behind the scenes), then the IdP will send a message back to Canvas saying (effectively) that it cannot terminate your IdP session as you no longer have one.

That’s when the error will be seen. It is no cause for concern, once you know about the workings between the two systems behind the scenes.