It seems google can't show me any page where those three words stand together (apache2, http2, gnutls), so no big hope anyway.
I have a working HTTPS apache2 server on Debian Stretch, with a let's encrypt certificate.
The configuration is functional with
http2 enabled, and I get the server to offer HTTP2 over HTTPS. ✅
However, when I disable
ssl and enable
gnutls — together it won't work —, I only get HTTPS and HTTP/1.1.
Can anyone tell for sure "it should [not] work because…"?