I never clean my cache. Just put it in the envelope and drop it in the box. If the campground host thinks it's dirty they can clean it before they pass it on. But if you ARE gonna launder money, don't hang it outside; it goes against the campground rules.
Seriously, I had the same problem for two days. Did an internet search for "what the heck?" and found nothing. Selected an rv.net hit and voila, no problem. Changed my favorites to a new accessible page.
I think it was an update (mine or theirs) that glitched. All good.