Many web server configurations face issues related to file permissions. It often renders the server inaccessible to visitors and manifests in the form of a 403 error. Usually, the error message is something like “Forbidden: you don’t have permission to access / on this server”. It can be anything in the form of Forbidden: you don’t have permission to access this resource.

Source: LXer – Solved: You Don’t Have Permission to Access on This Server