获取local.ERROR：异常'PDOException'，消息'SQLSTATE [HY000] [1044]访问被拒绝用户'''localhost'到数据库'forge''

Question

我偶尔会在我的本地环境（XAMPP）上收到此错误：

local.ERROR: exception 'PDOException' with message 'SQLSTATE[HY000] [1044] Access denied for user ''@'localhost' to database 'forge''

.Env文件编写如下：

APP_ENV=local
APP_DEBUG=true
APP_KEY=Dg4KFyDhAePtob94RUZ4frMCak4nHSF2

DB_HOST=localhost
DB_DATABASE=items
DB_USERNAME=root
DB_PASSWORD=

CACHE_DRIVER=file
SESSION_DRIVER=file
QUEUE_DRIVER=sync

配置/ database.php中：

<?php

return [


    'fetch' => PDO::FETCH_CLASS,

    'default' => 'mysql',

    'connections' => [

        'sqlite' => [
            'driver'   => 'sqlite',
            'database' => storage_path().'/database.sqlite',
            'prefix'   => '',
        ],

        'mysql' => [
            'driver'    => 'mysql',
            'host'     => env('DB_HOST', 'localhost'),
            'database' => env('DB_DATABASE', 'forge'),
            'username' => env('DB_USERNAME', 'forge'),
            'password' => env('DB_PASSWORD', ''),
            'charset'   => 'utf8',
            'collation' => 'utf8_unicode_ci',
            'prefix'    => '',
            'strict'    => false,
        ],

        'pgsql' => [
            'driver'   => 'pgsql',
            'host'     => env('DB_HOST', 'localhost'),
            'database' => env('DB_DATABASE', 'forge'),
            'username' => env('DB_USERNAME', 'forge'),
            'password' => env('DB_PASSWORD', ''),
            'charset'  => 'utf8',
            'prefix'   => '',
            'schema'   => 'public',
        ],

        'sqlsrv' => [
            'driver'   => 'sqlsrv',
            'host'     => env('DB_HOST', 'localhost'),
            'database' => env('DB_DATABASE', 'forge'),
            'username' => env('DB_USERNAME', 'forge'),
            'password' => env('DB_PASSWORD', ''),
            'prefix'   => '',
        ],

    ],

    'migrations' => 'migrations',

    'redis' => [

        'cluster' => false,

        'default' => [
            'host'     => '127.0.0.1',
            'port'     => 6379,
            'database' => 0,
        ],

    ],

];

这是Laravel 5.1。它很少发生，但它仍然会发生。

可能导致问题的原因是什么？