Briefly unavailable for scheduled maintenance. Check back in a minute.

How to Fix “Briefly Unavailable for Scheduled Maintenance. Check Back in a Minute” in WordPress

问题描述：在安装插件、主题升级时，如果刷新页面或者操作失败，会显示如下提示：

Briefly unavailable for scheduled maintenance. Check back in a minute.

解决方案：移除 ./.maintenance 文件。