That’s a sign that it’s an issue with your router. You need to test that by bypassing it and seeing if you can then connect successfully.
How about checking whether his ip is cloudflare banned first, eh?
Because bypassing the router only takes 60 seconds and if it works, then you’ve identified the problem as being the router and if it doesn’t work then you know it’s an IP block. Either way there’s no guessing.
in my case i would test that by resetting my modem, which changes my IP 
it doesnt take 60 seconds if you dont have a laptop and your computer is nowhere near your router
Instead of resetting the router, doing this and that to the router, updating the firmware to the router etc etc etc, simply bypass it and see if you can connect. If so, IT’S THE ROUTER.
He stated in his original post “it won’t work on any of my computers on my network.” That means he has other computers.
which might be equally far away from the router, and equally as annoying to move
all im saying, you dont know it isn’t much of a hassle for him
This is the same thing that happens on my network. On mine sometimes a website will give me fits no matter if I bypass the router, clear my cache, or run it on a mobile system including my phone or 3ds. There’s no way for me to visit the site unless I ctrl+F5 I know it sounds odd, but it’s true.
Give it a try now, I flushed the firewall blocks so if you were blocked you should be able to access it now.