I helped someone the other day who was having strange behavior in the File Manager and it turned out to be caused by a rule in the IIS Url Rewrite module to force all lower case urls. He did not even intend that rule to be applied to the mojoportal site, it was for another site, but I guess the way he configured it, it was applying to all sites.
This is just one example I know of, but anything that changes the urls before it gets to application code is a place where problems can be introduced, not just in mojoPortal but in any app, but especially in apps like mojoPortal that do their own url rewriting internally. And it can be difficult to diagnose for someone like me trying to provide support for problems and not knowing about such configuration that may have been done on the server that changes the web request before it gets to mojoPortal.
Best,
Joe