Let's Encrypt 根证书已于 2021/9/30 过期，qiandao.today 需要更新

[Rongronggg9]

https://letsencrypt.org/docs/dst-root-ca-x3-expiration-september-2021/

一些使用 LE 的网站已经出现 599：

时间	状态	日志
2 分钟前	失败	failed at 1/1 request, error:CurlError('HTTP 599: SSL certificate problem: certificate has expired',), https://www.iamtxt.com/e/extend/signin.php
10-3 12:16:34	失败	failed at 1/1 request, error:CurlError('HTTP 599: SSL certificate problem: certificate has expired',), https://www.iamtxt.com/e/extend/signin.php
10-3 1:16:24	失败	failed at 1/1 request, error:CurlError('HTTP 599: SSL certificate problem: certificate has expired',), https://www.iamtxt.com/e/extend/signin.php
10-2 14:16:14	失败	failed at 1/1 request, error:CurlError('HTTP 599: SSL certificate problem: certificate has expired',), https://www.iamtxt.com/e/extend/signin.php
10-2 3:16:04	失败	failed at 1/1 request, error:CurlError('HTTP 599: SSL certificate problem: certificate has expired',), https://www.iamtxt.com/e/extend/signin.php
10-1 16:15:54	失败	failed at 1/1 request, error:CurlError('HTTP 599: SSL certificate problem: certificate has expired',), https://www.iamtxt.com/e/extend/signin.php
10-1 10:15:44	失败	failed at 1/1 request, error:CurlError('HTTP 599: SSL certificate problem: certificate has expired',), https://www.iamtxt.com/e/extend/signin.php
10-1 6:15:43	失败	failed at 1/1 request, error:CurlError('HTTP 599: SSL certificate problem: certificate has expired',), https://www.iamtxt.com/e/extend/signin.php
10-1 4:25:34	失败	failed at 1/1 request, error:CurlError('HTTP 599: SSL certificate problem: certificate has expired',), https://www.iamtxt.com/e/extend/signin.php
10-1 4:15:24	失败	failed at 1/1 request, error:CurlError('HTTP 599: SSL certificate problem: certificate has expired',), https://www.iamtxt.com/e/extend/signin.php
9-30 4:15:04	成功	+1分,余额907,已连签61天