Back button issue

[Cantor, Scott]

The error you're getting is not ambiguous, it means exactly what it says: you have a request containing a flow execution key for a conversation with that client that does not exist (at all) on the target server.

That explicitly means:

* a stale URL/bookmark

* a deliberate server restart causing it to lose conversation state, which should be self-evident

* a request switched servers mid-conversation, indicating a load balancer issue, or bad handling of server maintenance (you can't avoid the issue completely but non-graceful server restarts across a cluster simply aren't a thing with this software, which is one reason Docker orchestration is such a bad fit)

* a cookie issue with the client such that it's not holding onto the JSESSIONID cookie value and getting it back to the server, preventing the container from getting back to the right session and the conversations stored in it

The IdP doesn't accumulate cookies the way the SP sometimes does, so usually cookie overflow issues are caused by load balancer cookies, not the IdP's.

That's basically the extent of the causes because of the specifics of the exception. Others have different sorts of causes, and there are dozens of cases that all lead to the same error page.

-- Scott