只做

apt-get install ca-certificate

We just had this same issue come up when we installed a newly minted certificate just this last week. I've also seen it two other times...yet I'm slow to learn. In all 3 cases I had to get the "intermediate certificates" and install them. In other words My cert was good but it's signer or it's signer's signer wasn't correctly installed. Make sure you go to your certificate provider's site and get the correct intermediate certificates and install them as well on your server and then this warning will go away.

可能不仅仅是上面的原因，也可能是客户没有更新列表……但我会确保这不仅仅是你没有完全安装正确的证书，然后再到客户端，并确保他们的列表更新。

不是完全一样的问题。在docker上，我正在将我的主机文件系统挂载到/etc，其中已经安装了OpenSSL certs，这将被覆盖。

改变安装到不同的文件系统可以解决这个问题。

如果您使用的是windows，只需转到控制面板，单击自动更新，然后单击windows更新网站链接。照着这一步做。至少这对我来说是有效的，没有更多的证书问题，即每当我像以前一样去https://www.dropbox.com。

apt-get install ca-certificates 

s起作用;)

首先，需要安装SSL证书。说明(基于https://stackoverflow.com/a/4454754/278488):

pushd /usr/ssl/certs
curl http://curl.haxx.se/ca/cacert.pem | awk 'split_after==1{n++;split_after=0} /-----END CERTIFICATE-----/ {split_after=1} {print > "cert" n ".pem"}'
c_rehash

以上已经足够修复curl了，但是wget需要一个额外的符号链接:

ln -sT /usr/ssl /etc/ssl