If a server responds with a redirect header where the server it is redirecting to is a server that is not available, Safari displays a misleading error message.
The following header issued by a page at http://localhost/redirect.php
> HTTP/1.1 301 Moved Permanently
> Location: http://klajdfkajsdfkjas.com
will result in this Safari error message:
> Safari can’t find the server.
> Safari can’t open the page “http://localhost/redirect.php” because it can’t find the server “localhost”.
But the server "localhost" is not the source of this problem, it's the server that the browser was requested to redirect to. Thus the error message should mention the adress that it is asked to redirect to. It would also be helpful if the kind of server response (301, redirect, etc.) would be shown on the error page. However, the exact wording is problematic in this case as not many users really understand the techniques of what is happening here.