求大神 DST Root CA X3证书过期怎么解决

别说你的旧系统，新系统都会有可以有这个问题。

英文的直接复制过来，如需自己翻一下：

macOS, iOS

Some operating systems hold onto the expired R3 > DST Root CA X3 chain even if your server is no longer using it. Try a restart of the affected client device.

For older macOS not updated by Apple:

• Download the ISRG Root X1 certificate file from http://x1.i.lencr.org/
• Open the Keychain Access app and drag that file into the System folder of that app.
• Find the ISRG Root X1 certificate in System and double click on it, open the Trust menu and change "Use System Defaults" to "Always Trust", then close that and enter your password to confirm the change (if prompted).

给你几个参考资料看一看：

https://www.openssl.org/blog/blog/2021/09/13/LetsEncryptRootCertExpire/

https://eclecticlight.co/2021/10/01/why-wont-safari-open-that-web-page/

https://forums.macrumors.com/threads/getting-ssl-errors-today-this-is-why.2314627/?post=30402387#post-30402387

最简单的办法是安装新的证书，DST Root CA X3是Let's Encrypt原先的交叉验证证书，现在淘汰了，从10月1日起他们改换了他们自己的ISRG Root X1证书，你把新的证书安装上应该就OK了，不过如果是浏览部分网页的话，可能还有中间证书，看你的时间来看的话应该是R3,如果你愿意捣鼓一下的话，可以在Chain of Trust - Let's Encrypt (letsencrypt.org)找到r3证书下载并安装在mac里就好了，或者直接用这个链接https://letsencrypt.org/certs/lets-encrypt-r3.der（取自前一个链接，贴前一个链接是为了方便你寻找你想要的证书）

主要是不確定這個證書是什麼時候更新的, 建議預約 Apple store 逐版本的升級, 到沒問題的時候就可以停止了

只能升級系統了