docker mysql hostname

I am developing a docker-compose file for my setup. Main issue I have is connecting from host to a working docker-container with mysql.

As my hostname I’m using the containername: “docker_mysql”, username & password as specified in the yaml file.

However, It always returns “connection failed”. I have granted the correct privileges to the root user, though still the same. Have also tried to connect via ip, and/or localhost - still same failing result.

Soon pulling my hair. After much search on google, still no solution.

Anyone can see what i’m doing wrong?

version: "3.9"
    services:
        mysql:
        image: mysql:5.7
        build: ./Docker/mysql
        container_name: docker_mysql
        restart: always
        ports:
            - "3308:3306"
        environment: 
            MYSQL_DATABASE: "xx"
            MYSQL_USER: "xx"
            MYSQL_PASSWORD: "xx"
            MYSQL_ROOT_PASSWORD: "xx"
        networks:
            - app_network
            
networks:
  app_network:
    driver: "bridge"

https://imgur.com/a/zGfTJjK.png