At the moment if you authenticate to your IdP with Qlik Sense SaaS and it fails for any reason, you end up back at a text-only JSON message in the browser.
This isn't very user-friendly as end users could end up at this page if, for instance, their admin hasn't added them to the group that has permission to use Qlik Sense in their IdP config. Just a nicer looking page with a note to check with your IT admin - and of course the specific error as is currently shown.
NOTE: Upon clicking this link 2 tabs may open - please feel free to close the one with a login page. If you only see 1 tab with the login page, please try clicking this link first: Authenticate me! then try the link above again. Ensure pop-up blocker is off.