this issue is back.
hitting “preview” within studio causes the 404 and the “refused to connect” message. i can get preview to work from the development tab on the dashboard
i tried that, when it first happened. no joy.
i also tried logging out and back in.
no joy.
for some reason, clicking the preview url link fixed it in studio, too.
so one would think it was a cache issue, but clearing the cache didn’t fix it, at least at first.