i am deploying my app on AWS instance. i have both frontend and backend as docker image.
i want to use nginx. when i run this config, and go to AWS given public URL, then 502 is returned by nginx.
/api
/docs
they are working but
/admin
/
returning 502.
here is my conf files:
docker-compose.yml:

  backend:
    container_name: backend
    image: ${BACKEND_IMAGE_NAME}:${IMAGE_TAG}
    command: python manage.py runserver 0.0.0.0:8000
    env_file:
      - .env
    expose:
      - 8000

  frontend:
    container_name: frontend
    image: ${FRONTEND_IMAGE_NAME}:${IMAGE_TAG}
    expose:
      - 3002
     
    env_file:
      - .env

  nginx:
    build: ./nginx
    ports:
      - 80:80
    depends_on:
      - backend
      - frontend

here is nginx conf:

upstream backend {
    server backend:8000;
}

upstream frontend {
    server frontend:3002;
}



server {

    listen 80;

    location /api/ {
        proxy_pass http://backend;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $host;
        proxy_redirect off;
    }

    location /docs/ {
        proxy_pass http://backend;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $host;
        proxy_redirect off;
    }

    location /admin/ {
        proxy_pass http://backend;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $host;
        proxy_redirect off;
    }

    location / {
        proxy_pass http://frontend;  # Proxy to frontend on port 3002
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $host;
        proxy_redirect off;
        
        # Ensure that Nginx handles large files and requests well
        client_max_body_size 100M;

        # Timeout settings to prevent 502 Bad Gateway
        proxy_connect_timeout 600;
        proxy_send_timeout 600;
        proxy_read_timeout 600;
        send_timeout 600;
    }
}```
  

nginx docker file:

FROM nginx:1.27

RUN rm /etc/nginx/conf.d/default.conf
COPY nginx.conf /etc/nginx/conf.d```

front end docker file:

# Use a Node.js base image
FROM node:18-alpine

# Set working directory
WORKDIR /app

# Copy package.json and install dependencies
COPY package*.json ./
RUN npm install

# Copy the rest of the application code
COPY . .

# Build the app for production
RUN npm run build

# Expose the port your app runs on
EXPOSE 3002

# Start the app
CMD ["npm", "run", "start"]

backend docker file:

FROM python:3.12

ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1

WORKDIR /app/src

COPY requirements.txt ./
RUN pip install --no-cache-dir -r requirements.txt
COPY . /app/

EXPOSE 8000