It's not Exede blocking traffic, their home router has a messed up routing. Please try to get a firmware update for this router.
This is the prudent smart thing to first do to check on firmware update regardless of when you would think. Then after that you can disable your A/V and go to RedFox and if that works then your Router isn't the problem. But a firmware update is something everyone should do if there is no update then disable the A/V and try RedFox to see what is really blocking it.It's not Exede blocking traffic, their home router has a messed up routing. Please try to get a firmware update for this router.
Then I suspect you got a A/V that is a problem and is blocking RedFox site, I see where the A/V would secretly put the block in without the user knowing about this only to find out when they try to get to a site that is blocked or unable to access. I know of Norton is one of those programs that do that. But since no one is there to see what the setup is you will have to do your diagnosing to find the problem as well. Since you said not a ISP or Router problem then next would be a A/V blocking problem.I'm not using their router so that can't be the issue.