我用mysql，phpmyadmin，php和mailhog设置了一个本地环境，但我不能用CakePhp连接到数据库。
我的连接数据在config/app.php：

'default' => [
          'className' => 'Cake\Database\Connection',
        'driver' => 'Cake\Database\Driver\Mysql',
        'persistent' => false,
        'host' => '172.21.0.4', => I tried localhost, mysql, 172.0.0.1 as well...
        'username' => 'root',
        'password' => 'root',
        'database' => 'mydb1',
        'encoding' => 'utf8mb4',
        'timezone' => 'UTC',
        'cacheMetadata' => true,
        'flags' => [],
        'log' => false,

当我通过mysqli_connect（）（直接在config/app.php中）测试连接时，它工作得很好：

$link = mysqli_connect("mysql", "root", "root",'mydb1',"3306",'');

if (!$link) {
echo "Error: Unable to connect to MySQL." . PHP_EOL;
echo "Debugging errno: " . mysqli_connect_errno() . PHP_EOL;
echo "Debugging error: " . mysqli_connect_error() . PHP_EOL;
exit;
}

echo "Success: A proper connection to MySQL was made!" . PHP_EOL;
echo "Host information: " . mysqli_get_host_info($link) . PHP_EOL;

$query = "SELECT * FROM test";
$result = mysqli_query($link, $query) or die(mysqli_error($link));
$flag = FALSE;

while ($row = mysqli_fetch_array($result, MYSQLI_BOTH)) 
{
    echo $row['test']."<br>";
}

mysqli_close($link);

非常感谢！来自奥地利的问候！