If you are receiving a 404 Error on a page, the reason could be that your browser is storing an old version of the page and cannot display it. The solution is to force your browser to delete the cached version and reload a fresh copy.

To do this, hold the Ctrl key on your keyboard while you press the refresh button with your mouse.  The refresh button looks like this:

and is usually located to the left or the right of the URL in the browser window.

If this doesn't work, there could be a different issue, such as an incorrect link. If doing a cache refresh does not resolve the 404 error, please open a ticket and provide the URL of the page that is having issues, as well as the page you were visiting prior to the 404 error.