title: Why Cypress can't detect running webserver?
body: <p>My containers are all running and I'm trying to run Cypress tests agaisnt it:</p>
  <p>docker-compose.yml:</p>
  <pre><code>version: '3.7'
  
  services:
    
    users:
      build:
        context: ./services/users
        dockerfile: Dockerfile
      volumes:
        - './services/users:/usr/src/app'
      expose:
        - 5000
      environment:
        - FLASK_APP=project/__init__.py
        - FLASK_ENV=development
        - APP_SETTINGS=project.config.DevelopmentConfig
        - DATABASE_URL=postgresql://postgres:postgres@users-db:5432/users_dev
        - DATABASE_TEST_URL=postgresql://postgres:postgres@users-db:5432/users_test
        - SECRET_KEY='hakuna matata'
      depends_on:
        - users-db
  
    client:
      build:
        context: ./services/client
        dockerfile: Dockerfile
      volumes:
        - './services/client:/usr/src/app'
        - '/usr/src/app/node_modules'
      ports:
        - 3007:3000
      environment:
        - CHOKIDAR_USEPOLLING=true
        - NODE_ENV=development
        - REACT_APP_USERS_SERVICE_URL=${REACT_APP_USERS_SERVICE_URL}
      depends_on:
        - users
  
    users-db:
      build:
        context: ./services/users/project/db
        dockerfile: Dockerfile
      expose:
        - 5432
      environment:
        - POSTGRES_USER=postgres
        - POSTGRES_PASSWORD=postgres
  
    nginx:
      build:
        context: ./services/nginx
        dockerfile: Dockerfile
      restart: always
      ports:
        - 80:80
      depends_on:
        - users
        - client
  </code></pre>
  <p>cypress.json:</p>
  <pre><code>{
      &quot;baseUrl&quot;: &quot;http://nginx:80&quot;,
      &quot;video&quot;: false
  }
  </code></pre>
  <p>docker ps:</p>
  <pre><code>CONTAINER ID   IMAGE          COMMAND                  CREATED          STATUS          PORTS                                       NAMES
  97f91a4b3a81   tdd_nginx      &quot;/docker-entrypoint.…&quot;   56 minutes ago   Up 56 minutes   0.0.0.0:80-&gt;80/tcp, :::80-&gt;80/tcp           tdd_nginx_1
  089cd20326c1   tdd_client     &quot;npm start&quot;              56 minutes ago   Up 56 minutes   0.0.0.0:3007-&gt;3000/tcp, :::3007-&gt;3000/tcp   tdd_client_1
  85dc333cc487   tdd_users      &quot;/usr/src/app/entryp…&quot;   56 minutes ago   Up 56 minutes   5000/tcp                                    tdd_users_1
  696298d0ab2c   tdd_users-db   &quot;docker-entrypoint.s…&quot;   56 minutes ago   Up 56 minutes   5432/tcp                                    tdd_users-db_1
  </code></pre>
  <p>error output:</p>
  <pre><code>Cypress could not verify that the server set as your `baseUrl` is running:           
  
  &gt; http://nginx:80                                                                  
                                                                                                                                                   
  Your tests likely make requests to this `baseUrl` and these tests will fail if you do
  n't boot your server.                                                                
                                                                                                                                                   
  Please start this server and then run Cypress again.
  </code></pre>
  <p>giving it <code>http://localhost</code> didn't work either.
  I'm running the test runner from container: <code>docker run -it -v $PWD:/e2e -w /e2e cypress/included:3.2.0</code></p>
  <p><strong>environment:</strong></p>
  <p>docker version 20.10.11, build dea9396</p>
  <p>Cypress  3.2.0</p>
  <p>OS: Ubuntu Linux 20.04</p>
  <p>Any suggestions are appreciated.</p>