Nginx doesnt loaded web page

I configured nginx and after building docker image and run sudo docker-compose up, it has no error, but the problem is web server with given host doesn't load:

Unable to connect

Firefox can’t establish a connection to the server at localhost:4200.

The site could be temporarily unavailable or too busy. Try again in a few moments.
If you are unable to load any pages, check your computer’s network connection.
If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the web.

I have defined nginx.conf file:

server {
    listen 80;

    location / {
        proxy_pass http://localhost:4200;  # Angular service
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }

    location /api/ {
        proxy_pass http://localhost:8000;  # Django service
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

And also I created Dockerfile for it:

FROM nginx:latest
COPY ./nginx.conf /etc/nginx/conf.d/default.conf

docker-compose for nginx:

nginx:
    build:
      context: .
      dockerfile: Dockerfile
    container_name: auralab-nginx
    ports:
      - "80:80"
    depends_on:
      # - angular
      - django

I tried both to put my actual server ip in proxy pass but doesn't work, it's 34.159.204.45.

Any solutions ?

The localhost address points to the container itself. Instead of using:

proxy_pass http://localhost:4200;

use:

proxy_pass http://angular:4200;

Where angular is service name, like nginx from docker-compose file