Nginx proxy_pass ssl nodejs socketio error

[codedmart]

I am trying to track down what is going on but an not having any success. I
am using nginx as a proxy for ssl in front of my nodejs app. The http api
works fine. I have the websocket on a separate subdomain. I connects
sometimes but I have a ton of these messages in the error_log:

upstream prematurely closed connection while reading response header from
upstream

Here is my current config:
https://gist.github.com/codedmart/7182a10da31fcaa5143c

Any help or ideas on what to look for would be great.

Thanks!

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,265176,265176#msg-265176