Amazon SES postfix relay on centos

Following at the letter the amazon SES tutorial:
http://docs.aws.amazon.com/ses/latest/DeveloperGuide/postfix.html

but auth is not working and giving errors like

No worthy mechs found
SASL authentication failed; cannot authenticate to server

and so on?

Make sure you have the proper auth libs installed

yum install cyrus-sasl cyrus-sasl-plain cyrus-sasl-md5