With ruby gems on Windows I got this error message:

Gem::RemoteFetcher::FetchError: SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed (https://rubygems.org/gems/minitest-5.5.1.gem)

I could solve it by following the steps in the gist of luislavena:
howto-manually-add-trust-cert-to-rubygems.md