Hmmm, this sounds like a dns issue.
If it is, the problem can't always be solved from your end, since your internet provider needs to get updated first
But sometimes it can be fixed with the following steps:
- I see you already rebooted your router, but just in case your internet provider didn't update yet then, please reboot it again
- Flush the dns on your computer, see this post for instructions
- Clear cache and close your browser (earlier attempt before flushing dns might have corrupted your cache, so please try again)
- Try if the game will load for you now