Requests that used map styles relying on Natural Earth Data shapefiles started to fail this night, after a failed shapefile update.
I fixed this for now by restoring these shapefiles from an older backup and excluding them from automatic updated for the time being.
Looks as if the Natural Earth Data site had its DNS entry expire last night, as all shapefile downloads just started to return invalid ZIP files, and the site itself only returns 404 “not found” results on its www subdomain, and what looks like a domain traders general site template on the domain name itself.
I created a bug report on the sites Github project page as this is the only other channel to reach them that I know about …