This exact same issue is impacting me and two other GW2 players in my household. It started on Thursday as well.
We have tried the following, without success:
Reinstalled GW2
Restarted router
Port forwarding on router
Password change
Contacted our ISP, they confirmed the problem is not on their end.
This issue is specific to GW2. All other games and websites function properly. Bumping this for attention to the issue