When using https you will need to supply password or using a certificate.
In your case looks like the certificate is not a valid one.
Try fixing it like this by telling git where to find the certificate:
// Add the certificate to your configuration file
git config --system http.sslcainfo "C:\Program Files (x86)\git\bin\curl-ca-bundle.crt"
Alternatively, you could disable SSL checks:
// or switch off SSL checks completely by executing:
git config --system http.sslverify false
Set this in your config to disable it only for the given url and not for all requests
[http "https://weak.example.com"]
sslVerify = false
http.sslVerify
Whether to verify the SSL certificate when fetching or pushing over HTTPS.
http.sslCAInfo
File containing the certificates to verify the peer with when fetching or pushing over HTTPS