SQLSTATE[HY000] [2002] Connection refused

Typecho_Db_Adapter_Exception: SQLSTATE[HY000] [2002] Connection refused in /www/wwwroot/shiwen.info/typecho/var/Typecho/Db/Adapter/Pdo.php:60
Stack trace:
#0 /www/wwwroot/shiwen.info/typecho/var/Typecho/Db.php(312): Typecho_Db_Adapter_Pdo->connect(Object(Typecho_Config))
#1 /www/wwwroot/shiwen.info/typecho/var/Typecho/Db.php(349): Typecho_Db->query(Object(Typecho_Db_Query), 1)
#2 /www/wwwroot/shiwen.info/typecho/var/Widget/Options.php(345): Typecho_Db->fetchAll(Object(Typecho_Db_Query), Array)
#3 /www/wwwroot/shiwen.info/typecho/var/Typecho/Widget.php(222): Widget_Options->execute()
#4 /www/wwwroot/shiwen.info/typecho/var/Widget/Init.php(27): Typecho_Widget::widget('Widget_Options')
#5 /www/wwwroot/shiwen.info/typecho/var/Typecho/Widget.php(222): Widget_Init->execute()
#6 /www/wwwroot/shiwen.info/typecho/index.php(18): Typecho_Widget::widget('Widget_Init')
#7 {main}