Do you have Apache/2.4.17+ ?
As far as I know, Debian hasn't put Apache 2.4.18 in their
stablerepo yet, therefore you might want to upgrade your Debian server to a
testingversion (I strongly recommend doing so, as you will get all your software up to date, which is extremely helpful if you are dealing with some tricky problems that are fixed in the latest version)
Confirm your Apache version with
Do you have https enabled?
http 2works on both http and https, yet most browsers support only
http 2over https
http2 module in Apache
Try this command
If you had other mods to be enabled, replace
http2with the desired module, you can find available modules in
Add protocols in Apache config file
Here I have my HTTP2 site