Just seem to be getting a 301 redirect to the warning page:
liamriley@Mac-Mini ~ $ curl -IL modem.test
HTTP/1.1 301 Moved Permanently
Location: http://192.168.100.1/rebind_warning.html
Date: Mon, 06 Feb 2023 08:28:34 GMT
Server: lighttpd
HTTP/1.1 200 OK
Content-Type: text/html
Accept-Ranges: bytes
ETag: "512586486"
Last-Modified: Thu, 11 Aug 2022 10:09:53 GMT
Cache-Control: no-cache, must-revalidate
X-Frame-Options: SAMEORIGIN
Content-Length: 62
Date: Mon, 06 Feb 2023 08:28:34 GMT
Server: lighttpd