Hi all, I'm new here and I'm having some problems but I hope someone can help me.

Situation: server with zimbra for domain.com
server with qmail for sub.domain.com

I'd like to use the zimbra server as a secondary MX for the sub.domain.com. Have I got to create a new domain in Zimbra named sub.domain.com?

I already tried this:
zmprov md domain.com zimbraMailCatchAllAddress @sub.domain.com
zmprov md domain.com zimbraMailCatchAllForwardingAddress @sub.domain.com

but I'm experiencing 554 error (relay access denied)

Thanks in advance for your help!