Mattermost, Inc.

Websocket redirection

Hello all,
I have a little problem and i hope i will find help here.

See my server architecture :

C1 ------> S1 <-----> S2 <----- C2

C1 / C2 : some users
S1 : serveur with mattermost
S2 : serveur

I need to find a way to make a redirection from S2 to S1. S2 will be able to see Mattermost.
I don’t have admin right on S1 and S2

For the moment, i do this on S2 :
socat TCP-LISTEN:8065,fork TCP:S1:8065

C2 are able to see mattermost but i have an error on it :
Please check connection, Mattermost unreachable. If issue persists, ask administrator to check WebSocket port.