我已将我的Laravel5.5项目上载到centos7服务器。现在，当我第一次运行“php artisan migrate”来加载数据库表时，我遇到了以下错误。
错误消息屏幕截图
这是我的.env db部分

DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=event
DB_USERNAME=root
DB_PASSWORD=testpass

我已经在mysql中创建了db。

[root@li129-226 event_management]# php artisan migrate
In Connection.php line 664:
SQLSTATE[HY000] [2054] The server requested authentication method unknown    to the client (SQL: select * from information_schema.tables where table_schema = event and table_name = migrations)
In Connector.php line 67:
SQLSTATE[HY000] [2054] The server requested authentication method unknown to the client
In Connector.php line 67:
PDO::__construct(): The server requested authentication method unknown to the client [caching_sha2_password]