Forgot to mention, this is what I get when I throw curl at kriesi.at from a server that CAN download the demo data –

HTTP/2 200
vary: Accept-Encoding,Cookie,User-Agent
cache-control: max-age=3, must-revalidate
cache-control: max-age=608400
expires: Sun, 16 Feb 2025 21:53:16 GMT
x-cdn: Avia Media
x-powered-by: Avia
content-type: text/html; charset=UTF-8
date: Sun, 09 Feb 2025 20:53:16 GMT
server: Apache