Our recently upgraded site has a little issue where if you hit the "home" tab, and then browse to where you want to go, everything works as intended. However, if you have a bookmark to take you straight to an inner tab, you get a page stating "HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable.  Please review the following URL and make sure that it is spelled correctly." I have copied the URL, hit the home page, and pasted it in only to have the page load perfectly fine. I believe it is caused because the home page grants access to "All Users" whereas the rest of the site only allows specific roles. Has user information/detection/authentication/etc changed between 4.7.0 and 5.6.8? And if so, how did it change? We're using our own method of authentication which was working on 4.7.0, so we believe something different within 5.6.8 is causing the problem.

I just created a new page with the same permissions as the pages experiencing the issues, it has the same error as the other pages when navigating straight to it (and, as with all the others, throws no error if you go Home first and then use site navigation to reach it).

The home page is the only page allowing "All Users" and it is the only page that functions. Prior to the upgrade, all pages functioned fine. After the upgrade, only the home page can be hit directly, anything filtering out users just servers up the page with the message from my original posting if the page is hit directly, or the page functions fine if the home page is hit first. Even crafting a URL that merely sends someone to the homepage and immediately redirects them to one of the "problem" pages bypasses the issue, but that is not a fix.