Setting up proxy server for Socket.io

I'm trying to setup nginx for Node.js/Socket.io + static files, here's my conf :

   upstream app_salewhalepro {
        server 127.0.0.1:5000;
        keepalive 8;
    }

# the nginx server instance
server {
    listen 0.0.0.0:443;
    server_name salewhalepro.com salewhalepro;
    access_log /var/log/nginx/salewhalepro.log;

    ssl on;
ssl_certificate /etc/ssl/certs/PositiveSSL.ca-bundle.crt;
ssl_certificate_key /etc/ssl/private/salewhalepro.key;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;

    location / {
      proxy_http_version 1.1;
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection "upgrade";
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header Host $http_host;
      proxy_set_header X-NginX-Proxy true;

      proxy_pass http://app_salewhalepro/;
      proxy_redirect off;
    }
    location /libs {
      alias /var/whaleAPI/app/public;
      access_log off;
      expires max;
    }
 }

the http address sends me to the default nginx page, which is fine, but the https doesn't work at all, is there anything wrong with my conf? I could swear that it's a copypaste of a working config I use on a different server.