Cannot log into mysql via Adminer, wondering if there is anything wrong with my docker-compose.yml

Version: '3'

Services:
  nginx:
    build:
      context: ./lde/nginx
    ports:
      - 80:80
    volumes:
      - ./www:/var/www/html
      - ./www/errors:/etc/nginx/html
      - ../node_modules:/node_modules
    depends_on:
      - php
  php:
    build:
      context: ./lde/php-fpm
    volumes:
      - ./www:/var/www/html
  db:
    image: mysql:8.0
    restart: always
    volumes:
      - ./db:/var/lib/mysql
    environment:
      MYSQL_USER: root
      MYSQL_ROOT_PASSWORD: toor
      MYSQL_DATABASE: expense
  adminer:
    image: adminer:4.8.1
    restart: always
    ports:
      - 8080:8080

I am building a docker based web application. Above is my docker-compose.yml, with all docker containers up and running, I navigate to localhost:8080 and provided the following details to the log in page of Adminer:

System: MySQL
Server: db
Username: root
Password: toor
Database: expense //I manually created a database 'expense' via command line

But got an error message: Access denied for user 'root'@172.18.0.3 (using password: YES), 172.18.0.3 is the ip address for adminer within the docker bridge network.

b0b1e is the container ID for mysql container; I could log into mysql server via command line: docker exec -it b0b1e mysql -u root but if I tried logging into mysql server via command line using: docker exec -it b0b1e mysql -u root -p, followed by typing in password toor, I would get

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

What have I done wrong here?

Found the issue,

• my existing mysql volume on my host machine had stored some strange configurations from my past attempts, and it was stopping me from creating a new user and a new password for this user

Solution is to delete the existing mysql volume on my host machine and start fresh.