2018/05/14 03:56:10 [error] 12959#0: *42285845507 client intended to send too large body: 1664288 bytes

Syntax:    client_max_body_size size;
Default:
client_max_body_size 1m;
Context:    http, server, location

Sets the maximum allowed size of the client request body, specified in the “Content-Length” request header field. If the size in a request exceeds the configured value, the 413 (Request Entity Too Large) error is returned to the client. Please be aware that browsers cannot correctly display this error. Setting size to 0 disables checking of client request body size.

http://nginx.org/en/docs/http/ngx_http_core_module.html#client_max_body_size