Ruby on Rails

I have web site that open ok in the browser - no errors or warnings about the certificate. When I open it with open(), I get the following error:

/Users/joe/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/net/http.rb:931: `SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed' (OpenSSL::SSL::SSLError)

from /Users/joe/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/net/http.rb:852:in `start'

from /Users/joe/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/open-uri.rb:318:in `open_http'

from /Users/joe/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/open-uri.rb:736:in `buffer_open'

from /Users/joe/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/open-uri.rb:211:in `block in open_loop'

from /Users/joe/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/open-uri.rb:209:in `catch'

from /Users/joe/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/open-uri.rb:209:in `open_loop'

from /Users/joe/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/open-uri.rb:150:in `open_uri'

from /Users/joe/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/open-uri.rb:716:in `open'

from /Users/joe/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/open-uri.rb:34:in `open'

from t.rb:13:in `<main>'

/Users/joe/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/net/http.rb:931:          raise exception

Trying another SSL enabled site (https://www.google.com) works ok.

Any ideas here?

Thanks,

Joe