nginx - recv() 502 bad gateway -Nginx +PHP7.4-fpm, Google Cloud ubuntu 实例

Question

我在 php7.4-fpm 上遇到了 502 bad gateway 同样的问题：

*3459 recv() failed (104: Connection reset by peer) while reading response
 header from upstream, client: {ip address}, server: {xxx.zzz.com}, request: "GET /xxx/yyy HTTP/1.1", up
stream: "fastcgi://unix:/var/run/php/php7.4-fpm.sock:", host: "{xxx.zzz.com}"

我在谷歌云虚拟机实例 nginx env 上运行这个服务器。请让我知道如何解决此问题。谢谢