nginx error: 500 error

My server :Django + Nginx + Gunicorn
when I call /articles/{id}  api, there was 500/502/504  error.
 
1. Gunicorn  concle error:
 

[2018-09-15 17:51:19 +0800] [22183] [CRITICAL] WORKER TIMEOUT (pid:22730)

 
2. nginx error file:

2018/09/15 16:49:44 [error] 1006#1006: *1274 upstream prematurely closed connection while reading response header from upstream, client: 27.154.27.176, server: waterlaw.cn, request: "GET /articles/6 HTTP/1.1", upstream: "[url=http://unix:/tmp/waterlaw.cn.socket:/articles/6"]http://unix:/tmp/waterlaw.cn.s ... ot%3B[/url], host: "waterlaw.cn", referrer: "[url=https://waterlaw.cn/"]https://waterlaw.cn/"[/url]

2018/09/15 17:07:17 [error] 1006#1006: *1338 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: 27.154.27.176, server: waterlaw.cn, request: "GET / HTTP/1.1", upstream: "[url=http://unix:/tmp/waterlaw.cn.socket:/"]http://unix:/tmp/waterlaw.cn.socket:/"[/url], host: "waterlaw.cn"

2018/09/15 17:10:47 [error] 22126#22126: *7 upstream prematurely closed connection while reading response header from upstream, client: 27.154.225.154, server: waterlaw.cn, request: "GET / HTTP/1.1", upstream: "[url=http://unix:/tmp/waterlaw.cn.socket:/"]http://unix:/tmp/waterlaw.cn.socket:/"[/url], host: "waterlaw.cn"

2018/09/15 17:14:26 [error] 22236#22236: *8 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 27.154.225.154, server: waterlaw.cn, request: "GET / HTTP/1.1", upstream: "[url=http://unix:/tmp/waterlaw.cn.socket/"]http://unix:/tmp/waterlaw.cn.socket/"[/url], host: "waterlaw.cn"

2018/09/15 17:16:03 [error] 22236#22236: *8 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 27.154.225.154, server: waterlaw.cn, request: "GET / HTTP/1.1", upstream: "[url=http://unix:/tmp/waterlaw.cn.socket/"]http://unix:/tmp/waterlaw.cn.socket/"[/url], host: "waterlaw.cn"

2018/09/15 17:43:44 [error] 22615#22615: *1 upstream prematurely closed connection while reading response header from upstream, client: 27.154.27.176, server: waterlaw.cn, request: "GET /articles/6 HTTP/1.1", upstream: "[url=http://unix:/tmp/waterlaw.cn.socket:/articles/6"]http://unix:/tmp/waterlaw.cn.s ... ot%3B[/url], host: "waterlaw.cn", referrer: "[url=https://waterlaw.cn/"]https://waterlaw.cn/"[/url]