Nginx Error_log Error Upstream timed out (110:connection timed out)

Recently migrated server, the site moved to the new server on the first day of the 504 error, the server and IP can ping, view the error log, found upstream timed out (110:connection timed out) error, the internet Baidu, The reason should be nginx configuration problem

Open/etc/php5/php-fpm/pool.d/www.conf

Change Pm.max_children to 40

Request_terminate_time modified to 900

Re-modify PHP.ini

Max_execution_time = 30, modify it for a longer time

Again in the/etc/nginx/site-avaiable/virtual host name
File Location ~ \.php$ {

}
In addition

Fastcgi_read_timeout 600;
Fastcgi_connect_timeout 600;
Fastcgi_send_timeout 600;
Fastcgi_buffers 2 256k;
Fastcgi_buffer_size 128k;
Fastcgi_busy_buffers_size 256k;
Fastcgi_temp_file_write_size 256k;

Nginx Error_log Error Upstream timed out (110:connection timed out)