|Attempts to access a Force.com may return Authorization Required error for a number of reasons, including:
- The page you are trying to access is part of a managed package, and the guest user does not have the appropriate managed package license.
- The Visualforce page you are trying to access has an error.
- When a Visualforce page has an error that does not have a Visualforce page assigned, the system attempts to return a standard page with details on the error.
- Force.com sites guest users cannot access standard pages, only Visualforce pages that have been added to the Site Visualforce Pages list for that site.
- This in turn results in an Authorization Required error, which by default has the Visualforce page "Unauthorized" assigned to it.