Been awhile since I been in here, so sorry for the delays.
Troubleshooting random websites not working can be a tricky one, Some basic stuff to do to help the provider or yourself troubleshoot the issue:
1.) Loading the providers website? YES/NO (If you have issues here the problem is most likely closer to you than the endpoint)
2.) Check your IP? Some providers will auto-blacklist these IP'S, if you got DHCP enabled IP Addr you might want to leave the router off for a night and you will get a new one.... Well you should)
3.) Traceroutes help however this is only the forward direction the route back from the endpoint might take another path.
4.) Isolate any firewalls or secondary routers. I see in the traceroutes here theres two internal hops.
5.) Use Ethernet no WiFi.
If your confidant to open Wireshark do a packet capture that can be extremely helpful.