Setting up eNewsletter with gmail account

We have a wordpress site hosted on Bluehost, and are trying to get our google email configured correctly in the setup. Keep getting error message SMTP Error: Could not connect to SMTP host. Mailer Error: SMTP Error: Could not connect to SMTP host. Have been trying different settings under eNewsletter settings, and can't seem to get it correct. What is the correct way to set this up? Thanks for any help.