gRPC via HTTP2 - do not work

I’m trying to make work one service hosted on openshift through HAproxy.
I have 2 host: <Host_G> - HAproxy gateway, <Host_T> - target openshift with exposed service.
Host_G & Host_T in different domains, no wildcard possible.


    mode http
    timeout connect 5000ms
    timeout client 50000ms
    timeout server 50000ms
    option http-use-htx

frontend https
    mode http
    bind *:443 ssl crt /etc/haproxy/pem/fullchain.pem alpn h2
    tcp-request content accept if { req_ssl_hello_type 1 }
    use_backend servers

backend servers   
    http-request set-header <Host T>
    mode http
    balance roundrobin  
    server <Host T> <Host_T_IP> ssl verify none sni req.hdr(Host) alpn h2

When I use this config with simple http requests, it works fine, Host_T returns all requested data. But when I use this config with software that uses gRPC - something go wrong. Program crashes with “Connection timeout”. Also I don’t see any traffic from Host_G to Host_T via tcpdump.
Request assistance. Sorry for poor english.