Connection refused nginx proxy for Docker containers

I’m trying to set up an nginx proxy pass between two docker containers. My frontend container seems to be working fine, but I’m getting a 502 error when trying to access the backend. I have two docker-compose files:

docker-compose.yml

version: "3.1"

services:
  backend:
    image: backend_image
    container_name: backend_container
  frontend:
    container_name: frontend_container
    image: frontend_image
  proxy:
    container_name: proxy_container
    image: nginx
    restart: unless-stopped
    ports:
      - "8080:80"
    depends_on:
      - website
      - frontend

docker-compose-development.yml

version: "3.1"

services:
  backend:
    container_name: backend_container_development
  frontend:
    build:
      context: ./site/public_html/frontend
      target: runner
    volumes:
      - ./site/public_html/frontend:/app
    command: npm run dev
    ports:
      - "3000:80"
    environment:
      NODE_ENV: development
  proxy:
    volumes:
      - ./nginx/local.conf:/etc/nginx/nginx.conf
      - ./logs:/var/logs

and my nginx local.conf file:

events {
    worker_connections 1024;
}

http {
    server {
        listen 80 default_server;

        location / {
            proxy_pass http://frontend:3000;
            error_log /var/log/frontend_errors.log;
        }

        location /api {
            proxy_pass http://backend:8000;
            error_log /var/log/backend_errors.log;
        }
    }
}

This is the error that I’m receiving

[error] 29#29: *2 connect() failed (111: Connection refused) while connecting to upstream, client: 192.168.48.1, server: , request: "GET /api HTTP/1.1", upstream: "http://192.168.48.3:8000/api", host: "localhost:8080"

I’ve verified that the IP for the backend and frontend container is 192.168.48.3 and that the container run separately on localhost:8000 and localhost:3000