HTTP/2 enable does not work

On Ubuntu 14.04.4 LTS with HHVM(HipHop VM 3.14.1) and Nginx(nginx/1.10.1)

I try to enable HTTP/2 like the following in my vhost

server {
    listen 443 ssl http2 default_server;
    listen [::]:443 ssl http2 default_server;

    root /var/www/mydomain;
    index index.html index.htm index.php;

    server_name mydomain.com;

    ssl_certificate /etc/nginx/ssl/www_mydomain_com.pem;
    ssl_certificate_key /etc/nginx/ssl/server.key;

    access_log /var/log/nginx/localhost.laravel-access.log;
    error_log  /var/log/nginx/locahost.laravel-error.log error;

    charset utf-8;

    location / {
        try_files $uri $uri/ /index.php?$query_string;
    }

    location = /favicon.ico { log_not_found off; access_log off; }
    location = /robots.txt  { log_not_found off; access_log off; }

    error_page 404 /index.php;

    include hhvm.conf;  # The HHVM Magic Here

    # Deny .htaccess file access
    location ~ /\.ht {
        deny all;
    }

    #Add Expires headers
    location ~* \.(?:ico|css|js|gif|jpe?g|png|jpg|woff|woff2)$ {
        expires 30d;
        add_header Pragma public;
        add_header Cache-Control "public";
    }
}

server {
    listen         80;
    listen    [::]:80;
    server_name    mydomain.com;
    return         301 https://$server_name$request_uri;
}

But, when I try to check at HTTP/2 test, I always get

Negative! mydomain.com does not support HTTP/2.0. Supported protocols: http/1.1

ALPN is not supported.

Edit

$ nginx -V as the following

nginx version: nginx/1.10.1
built with OpenSSL 1.0.1f 6 Jan 2014
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -fPIE -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -fPIE -pie -Wl,-z,relro -Wl,-z,now' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-ipv6 --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_addition_module --with-http_dav_module --with-http_geoip_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_image_filter_module --with-http_v2_module --with-http_sub_module --with-http_xslt_module --with-stream --with-stream_ssl_module --with-mail --with-mail_ssl_module --with-threads --add-module=/build/nginx-abUnII/nginx-1.10.1/debian/modules/nginx-auth-pam --add-module=/build/nginx-abUnII/nginx-1.10.1/debian/modules/nginx-dav-ext-module --add-module=/build/nginx-abUnII/nginx-1.10.1/debian/modules/nginx-echo --add-module=/build/nginx-abUnII/nginx-1.10.1/debian/modules/nginx-upstream-fair --add-module=/build/nginx-abUnII/nginx-1.10.1/debian/modules/ngx_http_substitutions_filter_module

How I can enable HTTP/2?