Hello

I’m trying to make my dockerized React app served by Nginx to connect to backend using the proxy_pass configuration in nginx.conf file and it keep throwing below error.

2021/03/03 23:41:35 [error] 28#28: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.21.0.1, server: 127.0.0.1, request: "POST /authentication/login/ HTTP/1.1", upstream: "http://127.0.0.1:5000/login/", host: "127.0.0.1:8888", referrer: "http://127.0.0.1:8888/login"

Both API backend and containerized React app are running on local. React is running on http://127.0.0.1:8888 and the API is running on http://127.0.0.1:5000.

My nginx.conf file is looking like below

upstream api_server {
  server 127.0.0.1:5000;
}

server {
  charset UTF-8;
  listen 80;
  root /usr/share/nginx/html;
  index index.html index.htm;

  server_name 127.0.0.1;

  location /authentication/ {
    proxy_pass http://api_server/;
  }

  location / {
    try_files $uri /index.html;
  }

  error_page   500 502 503 504  /50x.html;

  location = /50x.html {
    root   /usr/share/nginx/html;
  }
}

I’ve tried different variations of above, but same results. Can anybody suggest me how to resolve this issue?