#Increment timeout and max_children:

/etc/php/7.0/fpm/php.ini  =>   default_socket_timeout = 60000
/etc/php/7.0/fpm/php.ini  =>   pm.max_children = 20
/etc/php/7.0/fpm/pool.d/www.conf  =>   request_terminate_timeout = 60000

#Increment timeout on /etc/nginx/nginx.conf:
keepalive_timeout 65000;

#After Restart php-fpm and nginx:

sudo service php7.0-fpm restart
sudo service nginx restart