The HTTP/2 server reset the stream. HTTP/2 error code 'PROTOCOL_ERROR' (0x1)

[freakedenough]

WebOne HTTP Proxy Server 0.18.3-pre
Using Firefox 2.0.0.22 on Windows NT 3.51, I get this error:

01.09.2026 13:09:48.031+115931  >CONNECT science.orf.at:443 (192.168.50.62)
01.09.2026 13:09:48.356+124615  >[science.orf.at] GET /stories/3236389/ (192.168.50.62)
01.09.2026 13:09:48.356+129269  >Downloading content...
01.09.2026 13:09:48.356+351446   Cannot load this page: The HTTP/2 server reset the stream. HTTP/2 error code 'PROTOCOL_ERROR' (0x1). (HttpProtocolError).
01.09.2026 13:09:48.356+352018  <Return information page: WebOne: System.Net.Http.HttpProtocolException.
01.09.2026 13:09:48.356+354354  <Done.
01.09.2026 13:09:48.701+113466  >GET http://192.168.50.6:8082/webone.css (192.168.50.62)
01.09.2026 13:09:48.701+114236   Internal page: /webone.css
01.09.2026 13:09:48.701+116172  <Done.
01.09.2026 13:09:48.427+373130784       >[science.orf.at] GET /stories/3236389/ (192.168.50.62)
01.09.2026 13:09:48.427+373134423       >Downloading content...
01.09.2026 13:09:48.427+373366162        Cannot load this page: The HTTP/2 server reset the stream. HTTP/2 error code 'PROTOCOL_ERROR' (0x1). (HttpProtocolError).
01.09.2026 13:09:48.427+373368234       <Return information page: WebOne: System.Net.Http.HttpProtocolException.
01.09.2026 13:09:48.427+373370273       <Done.
01.09.2026 13:09:48.725+372855346       >GET http://192.168.50.6:8082/webone.css (192.168.50.62)
01.09.2026 13:09:48.725+372856082        Internal page: /webone.css
01.09.2026 13:09:48.725+372857796       <Done.

Navigating to the same site using IE11 on Vista, it works:

01.09.2026 13:20:35.387+148555  >CONNECT science.orf.at:443 (192.168.50.57)
01.09.2026 13:20:35.590+137357  >[science.orf.at] GET /stories/3236389/ (192.168.50.57)
01.09.2026 13:20:35.590+1006339 >Downloading content...
01.09.2026 13:20:35.590+2065959  200 OK. Body 31K of text/html; charset=utf-8 [Text].
01.09.2026 13:20:35.590+2109504 <Done.