[AlienRobot]

How are you trying to tell that?

If a web browser can't access a URL, it won't tell you why exactly because there's a chance it diagnosis the reason wrong and most users will be confused by that. I assume most diagnosis tools work the same way. You need to make assumptions about how the OS, hardware, and network are configured to be able to say "the problem is here."

For example, when you access a website, the first thing that needs to be done is check a domain name server (DNS) to get the IP address of the web server. But where does the web browser get the DNS IPs from? You can configure it in the browser. Or in the OS. Or in your router. Or in your modem. And if you don't, it gets them from the DHCP server the router connects to, which could be your ISP's DHCP server (then you get your ISP's default DNS) or it could also be some other router in an organization's network.

If the DNS seems wrong it's easy to tell the IP is wrong but it gets hard to say where that IP came from.

Even SSL could be a problem with the server having the wrong certificates or it could be your computer having the wrong certificates.