消息：mysqli：：real_connect（）：（HY000/2002）：在 docker 上运行的 phpmyadmin 中的连接被拒绝 - codeigniter

问：

我正在尝试将我的codeigniter php连接到phpmyadmin mysql数据库，两者都在docker容器上运行，但它说Message: mysqli::real_connect(): (HY000/2002): Connection refused Unable to connect to your database server using the provided settings.

我在 localhost：8082 中运行 phpmyadmin 我的codeigniter在localhost：8080中运行

这是我的数据库.php配置

$db['default'] = array(
    'dsn'      => '',
    'hostname' => '172.20.0.3',  // Use 'localhost' or '127.0.0.1' for a local MySQL database
    'username' => 'root',       
    'password' => 'testpassword',
    'database' => 'sortdb',     
    'dbdriver' => 'mysqli',   
    'dbprefix' => '',
    'pconnect' => FALSE,
    'db_debug' => TRUE,
    'cache_on' => FALSE,
    'cachedir' => '',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'encrypt'  => FALSE,
    'compress' => FALSE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => TRUE
);