This thread is a lot of blind-leading-the-blind answers.
I'm just one more blind man here, but I just had the same issue and solved it by following this easy article. As I understand the original question, git is trying to find an SSL cert file in order to use the HTTPS protocol, and failing to find the file. Most of the answers here seem to focus on "well, just disable SSL then," rather than replacing the file correctly.
This incantation should generate the cert file and put it in the correct location for git on cygwin:
$ curl -sL http://ca.pdinc.us > /etc/pki/ca-trust/source/anchors/ca.pdinc.us.pem \
&& update-ca-trust
In case you monkeyed with your git config (like I did) and need to set it BACK, this should do it:
$ git config --global http.sslcainfo "/etc/pki/ca-trust/extracted/openssl/ca-bundle.trust.crt"
One other side note which could be impacting many of the people reading this thread: The expected location of the cert file depends on which git executable you're running. Since we're talking about Cygwin, some (most?) of us probably have a Windows-native flavor of git installed too. If your Cygwin paths are set up to find the Windows git executable, your mileage may vary in terms of where to point the http.sslcainfo
configuration. To check which executable is getting picked up for you:
$ which git