Recieve email on Redmine Bitnami stack using imap and google mail gives error: SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed

Receive email on Redmine Bitnami 2.1.4 on Ubuntu 12.04 x64, using imap and google mail gives me the following error:

SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed

I used the command: rake redmine:email:receive_imap RAILS_ENV="production" \ host=imap.gmail.com username=myid@gmail.com password=my_passwrd ssl=1 port=993 \ project=support \ tracker=bug \ allow_override=project

any suggestion is much appreciated Thanks Ini