出现类似 It seems the CA server is busy now 问题：

[Tue Sep 24 10:42:36 EEST 2019] Getting domain auth token for each domain

[Tue Sep 24 10:52:39 EEST 2019] It seems the CA server is busy now, let’s wait and retry. Sleeping 1 seconds.

[Tue Sep 24 11:02:45 EEST 2019] It seems the CA server is busy now, let’s wait and retry. Sleeping 1 seconds.

排查错误（证书官方针对此问题说明）：

Today we have transitioned to a new CDN for the Production API. The change should already be visible worldwide. We expect that this change will not affect any client software.

We had previously made this transition for the Staging API: New CDN for the Staging API

With the new CDN, we have the opportunity to terminate TLS ourselves. The most visible change will be that the API will present a different TLS certificate. This will validate normally. We’ll also be able to make more agile ciphersuite changes in the future.

If you notice changes to API availability or behavior, please bring this to our attention here in the community forum. Thank you!

问题原因：Let’sEncrypt 证书已更新证书API接口，使用acme.sh生成证书的客户，需升级到新版acme.sh来更正此问题。

解决方法：

https://github.com/Neilpang/acme.sh

cd /usr/local/acme.sh

acme.sh --upgrade

升级成功

更新域名证书：

acme.sh --renew -d 您的域名

更新完成！