Solution to error "SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed"

README.md

Another solution

Get the latest cacert.pem file from wget http://curl.haxx.se/ca/cacert.pem And set these two ENV vars
export SSL_CERT_DIR=/path-to_pem_dir
export SSL_CERT_FILE=/path-to_pem_file

Best solution

Re-install your rvm ruby version without the binary.
rvm uninstall <your_ruby_version>
rvm install <your_ruby_version> --disable-binary

omniauth.rb

# frozen_string_literal: true

OmniAuth.config.logger = Rails.logger

Rails.application.config.middleware.use OmniAuth::Builder do
  provider :google_oauth2,
           ENV['OAUTH_CLIENT_ID'],
           ENV['OAUTH_CLIENT_SECRET'],
           client_options: {
             ssl: {
               ca_file: Rails.root.join('cacert.pem').to_s
             }
           },
           scope: 'email, profile, https://www.googleapis.com/auth/calendar',
           hd: 'example.com'
end