Gitlab:Peer's Certificate issuer is not recognized

Had faced the same problem after enabling verbose mode by following command export GIT_CURL_VERBOSE=1 and found the following issue:

NSS error -8179 (SEC_ERROR_UNKNOWN_ISSUER)

Found this following site helpful,But its good when you have entire control for the proxy server as well to enter the certificates.

http://dropbit.com/?p=168

I instead ran following command to bypass ssl verification by porxy server and it worked

git config --global http.sslVerify "false"

You need to configure /etc/gitlab/gitlab.rb. Change this line

nginx['ssl_certificate'] = "/etc/gitlab/<your-local-path>/cert.pem"

to

nginx['ssl_certificate'] = "/etc/gitlab/<your-local-path>/fullchain.pem"

(Assuming, you already have nginx enabled and you have correctly issued certificates, e.g. from LetsEncrypt.)

then restart gitlab and you're done:

$ gitlab-ctl reconfigure

Why - cert.pem does not contain full certificate chain, thus ca chain cannot be verified. Replacing with fullchain.pem solves it.