I was playing with One Identity Cloud Access Manager this afternoon and hit into "Not Authorized - Sorry, but it seems as if you're not authorized to access the selected application".
This is what I have observed. If the administrator configured a new protected application after you have logged in to the Application Portal (a one-stop landing portal for you to single sign-on to multiple protected backend applications), the new application link (e.g. Web SVN (Management)) will immediately appear on the portal.
However, as soon as you click on the new link, you'll hit into "Not Authorized" error.
To workaround this, log out and log in again. The new link is now accessible.