我知道已经有很多答案了。对于那些使用专用网络(如Zscaler等)的用户来说，如果需要更新rootcert，则可能会出现此错误。如果在Windows机器上使用WSL，这里有一个关于如何实现此更新的解决方案:

#!/usr/bin/bash

# I exported the Zscaler certifcate out of Microsoft Cert Manager.  It was located under 'Trusted Root Certification > Certificates' as zscaler_cert.cer.
# Though the extension is '.cer' it really is a DER formatted file.
# I then copied that file into Ubuntu running in WSL.

# Convert DER encoded file to CRT.
openssl x509 -inform DER -in zscaler_cert.cer -out zscaler_cert.crt

# Move the CRT file to /usr/local/share/ca-certificates
sudo mv zscaler_cert.crt /usr/local/share/ca-certificates

# Inform Ubuntu of new cert.
sudo update-ca-certificates 

最后，添加http。Sslverify到你的.git/config。

[core]
    repositoryformatversion = 0
    filemode = true
    bare = false
    logallrefupdates = true
[remote "origin"]
    url = https://server/user/project.git
    fetch = +refs/heads/*:refs/remotes/origin/*
[branch "master"]
    remote = origin
    merge = refs/heads/master
[http]
        sslVerify = false

我搞砸了我的CA文件，而我设置goagent代理。不能从github拉数据，并得到相同的警告:

服务器证书验证失败。CAfile: /etc/ssl/certs/ca-certificates。crt CRLfile:无

使用Vonc的方法，从github获取证书，并将其放入/etc/ssl/certs/ca-certificates。Crt，问题解决了。

echo -n | openssl s_client -showcerts -connect github.com:443 2>/dev/null | sed -ne '/- begin CERTIFICATE-/，/- end CERTIFICATE-/p'

GIT_CURL_VERBOSE=1 git [clone|fetch]…

应该能告诉你问题在哪里。在我的例子中，这是因为cURL在基于NSS构建时不支持PEM证书，因为这种支持在NSS中不是主线(#726116 #804215 #402712等等)。

也有同样的问题。由自己颁发的证书颁发机构引起。 通过在/usr/local/share/ca-certificates/中添加.pem文件解决 和调用

sudo update-ca-certificates

PS:“/share/ca-certificates”文件夹下的pem文件必须有扩展名。crt

Linux/Debian使用:

sudo cp /etc/ca-certificates.conf /etc/ca-certificates.conf.orig
sudo nano /etc/ca-certificates.conf
Change “mozilla/DST_Root_CA_X3.crt” in “!mozilla/DST_Root_CA_X3.crt” an save
sudo update-ca-certificates

https://talk.plesk.com/threads/lets-encrypt-root-certificate-expiration-on-30-september-2021.362224/