proxy - HaProxy for game servers, what's wrong with my configuration?

I host a website with a game client that uses TCP for connections. I am currently looking for a way to proxy my connections from one server to my origin server. I have tested Iptables forwarding and I have found that whilst it works HaProxy seems to perform better. The problem I'm facing is HaProxy randomly disconnects users after a random time of their connection being open. It's often less than 2 minutes. I'm quite new to Linux and of course I am a novice to haProxy.

Here my configuration, the origin IP address has been removed for obvious reasons:

global
daemon
maxconn 1000

defaults
    mode tcp
    timeout connect 5000ms

    timeout client 5000ms
    timeout server 5000ms

frontend proxy-in
    mode tcp
    bind *:1233
    default_backend proxy-out

backend proxy-out
    mode tcp

    server s1 127.0.0.1:1232

listen admin
    bind *:7772
    stats enable

Thank you. More details can be provided (if needed).