Relay Access Denied on some domains, not on all

==== Required information ====
- iRedMail version: 0.9.0
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): nginx
- Linux/BSD distribution name and version:  Debian 7
- Related log if you're reporting an issue:
====

Hi there,

For some reason my first two domains work as charm. The other domains I've added via iredadmin don't work. Or atleast: I can sent mail and if people reply on my mail I'll receive them, but if people sent me a new message (without a reply) they get a 554 5.7.1 Relay access denied.

I really have no idea why it is working for two domains, but not working for the three others.

Please help me out.

Thanks in advance.