尝试分析
首先根据提示，我判断是CA证书过期。于是对证书进行了更新
update-ca-trust
但是依然没有解决问题。之后，尝试了很多方法后，重新回来想想，为什么不适用curl -v来获取更多信息呢？于是使用该命令进行再次尝试。
[root@localhost ~]# curl https://www.baidu.com -v
NSS error -8179 (SEC_ERROR_UNKNOWN_ISSUER)
参考：https://www.cnblogs.com/xuxinkun/p/5417836.html
参考：https://*.com/questions/275878/firefox-and-ssl-sec-error-unknown-issuer
Just had the same problem with a Comodo Wildcard SSL cert.
After reading the docs the solution is to ensure you include the certificate chain file they send you in your config i.e.
SSLCertificateChainFile /etc/ssl/crt/yourSERVERNAME.ca-bundle