atasi nginx 504 Gateway Timeout

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;