==== Required information ====
iRedMail version (0.9.2):
- Linux/BSD distribution name and version: centos 6.6
- Store mail accounts in which backend (MySQL/
- Web server (Apache ):
- Manage mail accounts with iRedAdmin-Pro? yes
- Related log if you're reporting an issue:
====
I have 3 offices today each with its own server.
north.domain.com
south.domain.com
central.domain.com

I try to create a server where all addresses would be user@domain.com instead of user@south.domain.com etc.
but to continue to receive email for the old addresses until all are expired. but the server refuses the email

454 4.7.1 <user@south.domain.com>: Relay access denied;

second question: why is it a 4xx error and not a 5xx?