-Open your nginx.conf file located in /etc/nginx directory
-Add this below piece of code under http { section
client_header_timeout 3000;
client_body_timeout 3000;
fastcgi_read_timeout 3000;
client_max_body_size 32m;
fastcgi_buffers 8 128k;
fastcgi_buffer_size 128k;
Note – If its already present , change the values according.
That’s it. Reload Nginx and php5-fpm.
service nginx reload
service php5-fpm reload
If the error persists ( which is rare ), consider increasing the values.