SMTP works , incoming emails lost...

1- hostname set to its own nameservers ns1.hostname.com
2- hostname email works fine.
3- addon domain was added with ns1.hostname.com as ns server.
4- i can send emails from addon email account but cant receive any emails…

somewhere emails are lost…

ive added the domain to postfix.cnf as follows:

mydestination = mail.addondomain.com, localhost, localhost.localdomain
virtual_alias_domains = addondomain.com

any help?