[SOLVED] Docker Mattermost / NGINX Websocket Error 400

Troubleshooting
1

I have a docker mattermost running and it works perfectly when opened directly through server IP and Docker mapped port (192.168.0.5:33000) Everything works great.

The problem is when I try to make it work through NGINX proxy. The website itself works, I can login and go into channels and everything, but when typing a message I get:

WebSocket connection to ‘wss://chat.spntt.com/api/v3/users/websocket’ failed: Error during WebSocket handshake: Unexpected response code: 400, and I get the “Please check connection, Mattermost unreachable, if issue persists, ask administrator to check WebSocket port.”

And this repeats for every message typed in chat. I tried adding additional nginx rules as below but is still does not work.

location /api/v3/ {
proxy_pass http://192.168.0.5:33000;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection “upgrade”;
proxy_set_header Host $host;
}

2

Fixed by adding ^~

location ^~ /api/v3/ {
proxy_pass http://192.168.0.5:33000;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection “upgrade”;
proxy_set_header Host $host;
}

3

Glad to hear your issue is resolved @BobTB!

4

Hi @BobTB is this configuration working? I’ve added to my main server NGINX file and the websocket connection keeps failing.

Maybe you could help me: WebSocket not working on Server behind reverse proxy

5

The above mentioned configuration also is missing the websocket specific locations. Please check out the official documentation on how to set up the nginx proxy:

https://docs.mattermost.com/install/config-proxy-nginx.html