Unable to send emails due to authentication issue

Unable to send emails due to authentication issue

I had to change my password on Google email and now I can not send emails from inside the Zoho

I am getting the following error

Error while processing the request! Unable to connect SMTP server:smtp.gmail.com Reason:Authentication failed:535-5.7.8 Username and Password not accepted. Learn more at 535 5.7.8 http://support.google.com/mail/bin/answer.py?answer=14257 oj16sm1350543pdb.77 - gsmtp

I could not find where I need to change my Google authentication since I am connecting via Google App account and there is not need to authenticate again.

This is urgent, I can not respond to my customers. I am using email templates.

Rami