WebSocket error in the console log when running in a production environment

When running in a production environment the following appears in the console log:

```
72c927d1ec99268c15e921c80ce491f6d533e8bc.js?meteor_js_resource=true:61 WebSocket connection to 'wss://itmi.kheops.online/sockjs/175/6aalrx3p/websocket' failed: Error during WebSocket handshake: Unexpected response code: 400
```

There are no other ill-effects however.