Nginx Reverse Proxy Failure in Docker Container

Question

I am new to Docker and nginx and am in the process of setting up a reverse proxy with nginx for my react web application. I am using Docker to contain the application, and I have another Docker container for the proxy. Both have separate nginx.conf files.

I have reached the point where my proxy request returns a 502 - Bad Gateway, and am not sure why the proxy is not forwarding to my web application. Thanks for any help in advance. Anything is appreciated.

Update: The specific error message coming from the log is: connect() failed (111: Connection refused) while connecting to upstream, client: 192.168.192.1, server: 127.0.0.1, request: “GET / HTTP/1.1”, upstream: “http://127.0.0.1:3001/”, host: “localhost:3002” ^ The problem with that error message is that http://127.0.0.1:3001/ takes me straight to my web application. Therefore, it does not make sense for the connection to be refused since something is running on that port.

Proxy conf:

upstream my_project {
    server 127.0.0.1:3001 weight=3 max_fails=0;
}

server {
    listen 3002;
    server_name 127.0.0.1;

    location / {
        proxy_pass http://my_project/;
        proxy_redirect default;
    }

    location /favicon.ico {
        log_not_found off;
    }
}

Application conf:

server {
    listen 3001;
    listen [::]:3001;
    server_name localhost;
    gzip on;
    gzip_types text/plain text/html application/xml application/javascript;
    gzip_min_length 1000;
    root /usr/share/html;

    location / {
        root /usr/share/html;
        index index.html index.htm;
        try_files $uri $uri/ /index.html;
    }
}