Nginx modifies the front end request size limit (413 request entity too large)

During use of NGINX, if the request message is too large in the front-end POST request, it is usually necessary to increase the value of the client_max_body_size property, which defaults to 1M. Avoid 413 Request Entity Too Large.
You can optionally set it in HTTP {} : client_max_body_size 20m; Controls all requests received by NGINX
You can also optionally set it in Server {} : client_max_body_size 20m; Controls the requests received within the server
You can also optionally set client_max_body_size 20m in Location {}; Controls the request that matches the routing rules of Location

Read More: