This is the generic HTTP status code that a server returns to your browser when access to a requested page is denied. For instance, this can happen if you try to open a web page without first entering a user name and password.
A 403 error means you have hit an access control limit on a web page. In short, you are trying to view something to which you do not have access. The error may be from a failed authentication (wrong password or user ID) or a website not visible to those who are not logged in.