I have setup gunicorn with 3 workers 30 worker connections and using eventlet worker class. It is setup behind Nginx. After every few requests, I see this in the logs.
I had very similar problem, I also tried using "runserver" to see if I could find anything but all I had was a message Killed
Killed
So I thought it could be resource problem, and I went ahead to give more RAM to the instance, and it worked.