The HTTP error 403 occurs when one tries to access a website page that does not allow access. In most cases, this error occurs when one tries to navigate directories of a website on the server. This kind of access is usually denied regardless of authentication. In some cases, the error may occur when a website has not been updated, or the page that is being accessed has been removed. Certain patterns of HTTP traffic may also be disallowed, thus displaying the HTTP error 403.
Confirm that this is an authentic 403 error by checking to see if the URL ends in a slash (/). If this is the case, then you have been blocked from navigating a directory displaying directory listings or there is no content in the given directory.
Provide some content to the directory, either through your ISP or directly yourself. This content is usually in the form of HTML files. In case of the home page, ensure that it is titled "index.html."
Contact your ISP and confirm that the Web pages you have uploaded have been authorised for public access via the Internet. If this is not done, then the HTTP error 403 will keep recurring since access to the files will be restricted.
Ensure the website is open to all casual Internet users. Otherwise, a 403 error message might be issued. In most such cases, however, a 403 error message for "Not Authorized" is issued.
Test for a redirect to the appropriate Web page if you have recently changed an aspect of the website using a different computer and a different Internet connection. If the error shows up even after a considerable amount of time has passed, then consider checking the website set-up for deeper problems.
Check the defensive security policy of the Web server if 403 errors persist.
Check if your address is blacklisted. This may happen if you have been assigned an address that has made excessive access to the website. Your ISP can then assign you a new address.
Check if the site is still active. When a site is disabled, an HTTP 403 error may be generated.
Log in from the page that referred you to this page. Alternatively, this can be done in the default page of the website--for example, the home page.
Logging in before accessing Web pages allows your browser to store authorisation information called cookies, allowing you to navigate the Web pages error-free.