Invalid SSL certificate when pushing to Git server

Git for Windows has its own trust store of trusted certificates which is normally located in the file

• Git for Windows <=1.9: [Git installdir]\bin\curl-ca-bundle.crt (e.g., C:\Program Files (x86)\Git\bin\curl-ca-bundle.crt; configured by the key http.sslCAinfo in [Git installdir]\etc\gitconfig).
• Git for Windows >= 2.0: [Git installdir]\mingwXX\ssl\certs\ca-bundle.crt where XX stands for 32 or 64 (e.g., C:\Program Files\Git\mingw64\ssl\certs\ca-bundle.crt; configured by the key http.sslCAinfo in git config, e.g. C:\ProgramData\Git\config, C:\Program Files\Git\etc or your global/local config).

Disabling checking of certificates (e.g., by setting git config http.sslVerify false) is not a good idea and might be extremely dangerous (as all security checks are disabled and MitM attacks are easily possible - depending where this is set it applies for all new https connections).

In order to add a certificate (may it be a self-signed one or another root certificate) to this trust store in order to automatically trust it, you have to perform the following steps (the first five steps are just to gather the certificate, this can also be done with your favorite browser, but might require different tasks):

1. Open the URL of the site in Internet Explorer
2. Click on the lock symbol in the local bar and choose "Show certificates" (or choose Properties of the site and click on "Certificates")
3. (Optional) Select the certificate you want to trust on the certificate chain (third tab) and open it
4. Go to the second tab "Details"
5. Click on "Save to file", choose "Base64-encoded X.509 (.CER)" and save it with a unique name (remember that name; a name w/o spaces is recommended).

6. Now you have several options

   1. Use a separate certificate trust store which only contains your just downloaded cert, by executing git config --global http.sslCAinfo "[yourfilename]" in a cli shell in order to only use this certificate as the trust store.
   2. Use a separate certificate trust store which contains your just downloaded cert and all certificates from the git trust store, by appending all content from the system trust store file (path see above) and then execute git config --global http.sslCAinfo "[yourfilename]" in a cli shell in order to use this new trust store.
   3. Update the system certificate file, by appending the content of your just saved file to [path-to-git-trust-store-crt-file] (e.g. by type [yourfilename] >> [path-to-git-trust-store-crt-file] in a cli shell running with administrative rights) OR using notepad (make a copy of the ca-bundle.crt file on desktop, append the content of the downlaoded .crt file and then copy it back). Disadvantage: changes might get overwritten on git update

Done. Now, this certificate is in the trust store of Git for Windows.