could not connect to smtp host for gmail in php mailer?

could not connect to smtp host for gmail in php mailer?

I am using php mailer extension in yii framework to send mail. when i
configured smtp with my authenticated gmail user name and password and
send mails, everything working fine in my localhost(Wamp server). When i
hosted it into my server and tested sending mail, i was successfully able
to send mail for smtp.live.com and smtp.mail.yahoo.com but i get a error
"Could not connect to smtp host".
How to fix it?
Also what should happen when i give smtpAuth = false and try to send mail?
I was not able to send mail if my smtpAuth is false. Should i need to give
username and password even for smtpAuth = false?