works in browser but 502 status when directly connecting to websocket

[foysalit]

Mup version (mup --version): 1.5.1

Mup config

{
  "servers": {
    "one": {
      "host": "1.2.3.4",
      "username": "ubuntu",
      "pem": "~/.ssh/pem"
    }
  },
  "app": {
    "name": "my-app",
    "path": "../",
    "servers": {
      "one": {}
    },
    "buildOptions": {
      "serverOnly": true
    },
    "env": {
      "ROOT_URL": "https://subdomain.host.com",
      "MONGO_URL": "mongodb://user:pass@subdomain.subdomain.host.com:27017/rift-app",
      "VIRTUAL_HOST": "api.theriftapp.com",
      "HTTPS_METHOD": "redirect",
      "LETSENCRYPT_HOST": "api.theriftapp.com",
      "LETSENCRYPT_EMAIL": "email@domain.com",
      "VIRTUAL_PORT": 3000,
      "HTTP_FORWARDED_COUNT": 1
    },
    "docker": {
      "image": "abernix/meteord:node-12-base",
      "stopAppDuringPrepareBundle": true,
      "imagePort": 3000
    },
    "enableUploadProgressBar": true,
    "type": "meteor"
  },
  "proxy": {
    "domains": "api.theriftapp.com",
    "ssl": {
      "forceSSL": true,
      "letsEncryptEmail": "email@domain.com"
    }
  }
}

Thank you for this amazing package. I have this peculiar problem where the app is deployed on aws ec2 and it all works fine in browser. However, I can't connect using websocket directly. The app runs at https://api.theriftapp.com and it all works when loaded through the browser. If I try to connect using new WebSocket('wss://api.theriftapp.com') or using wscat it throws a 502 error. This is the output from nginx log:

[error] 177#177: *75 upstream prematurely closed connection while reading response header from upstream, client: 82.xx.xx.xxx, server: api.theriftapp.com, request: "GET / HTTP/1.1", upstream: "http://172.17.0.4:3000/", host: "api.theriftapp.com"

Which leads me to believe that I might need some kind of extra nginx config and was hoping that someone can shed some light on the direction I need to take to figure it out.

[foysalit]

Ok I'm just a dummy, connecting to new WebSocket('wss://api.theriftapp.com/websocket') works just fine as expected. I was just missing the websocket suffix.