解决Let's encrypt "too many failed authorizations recently"

今天申请 SSL 的时候遇到了下面这个问题

An unexpected error occurred: There were too many requests of a given type :: Error creating new order :: too many failed authorizations recently: see https://letsencrypt.org/docs/rate-limits/

我的解决方案是：

在 /etc/letsencrypt/accounts 里删除所有内容，然后即可继续申请