Docker with Apache, PHP and Elasticsearch

Question

I'm trying to get Elasticsearch connected on Docker. However it's not working. When doing the setup for Magento 2 it comes back with:

Could not validate a connection to Elasticsearch. No alive nodes found in your cluster

When I try curl elasticsearch:9200 it returns

curl elasticsearch:9200
{
  "name" : "5d0ed8e61816",
  "cluster_name" : "docker-cluster",
  "cluster_uuid" : "VNGqQCgWSvOoBOwmZmHTOQ",
  "version" : {
    "number" : "7.13.2",
    "build_flavor" : "default",
    "build_type" : "docker",
    "build_hash" : "4d960a0733be83dd2543ca018aa4ddc42e956800",
    "build_date" : "2021-06-10T21:01:55.251515791Z",
    "build_snapshot" : false,
    "lucene_version" : "8.8.2",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },
  "tagline" : "You Know, for Search"
}

I'm new to Docker, so I guess it's a rookie mistake?..

Here is my docker-compose.yml

version: '3'
services:
    web:
        image: runner668/php-apache-dev:7.4
        container_name: web
        restart: always
        user: application
        environment:
          - WEB_DOCUMENT_ROOT=/var/www/html
          - PHP_DATE_TIMEZONE=EST
          - PHP_DISPLAY_ERRORS=1
          - PHP_MEMORY_LIMIT=8096M
          - PHP_MAX_EXECUTION_TIME=300
          - PHP_POST_MAX_SIZE=500M
          - PHP_UPLOAD_MAX_FILESIZE=1024M
          - ELASTICSEARCH_HOST=elasticsearch:9200
        volumes:
          - /Volumes/Int/Docker/project-community-edition:/var/www/html
        ports:
          - "80:80"
          - "443:443"
          - "32823:22"
        links:
          - mysql
    mysql:
        image: mariadb:10.3.16
        container_name: mysql
        restart: always
        ports:
          - "3306:3306"
        environment:
          - MYSQL_ROOT_PASSWORD=root
          - MYSQL_DATABASE=magento
        volumes:
          - db-data:/var/lib/mysql
    phpmyadmin:
        container_name: phpmyadmin
        restart: always
        image: phpmyadmin/phpmyadmin:latest
        environment:
          - MYSQL_ROOT_PASSWORD=root
          - PMA_USER=root
          - PMA_PASSWORD=root
        ports:
          - "8080:80"
        links:
          - mysql:db
        depends_on:
          - mysql
    elasticsearch:
        image: elasticsearch:7.13.2
        container_name: elasticsearch
        environment:
          - discovery.type=single-node
          - "ES_JAVA_OPTS=-Xms512m -Xmx512m"
        ports:
          - "9200:9200"
          - "9300:9300"
        depends_on:
          - "web"
        volumes:
          - elasticsearch-data:/usr/share/elasticsearch/data
volumes:
    db-data:
        external: false
    elasticsearch-data:
        external: false