Hi. Have those configuration:

Zimbra server: IP, domain name mail.company.com

Send emails from relay smtp-out.provider.com

If messages are created on server from web interface and send to external recipient, example *@gmail.com - all good, but messages from server example zimbra@mail.company.com have error:

Host or domain name not found=name service error for name=smtp-out.provider.com type=mx: host not found, try again

I have local DNS where i have zone company.com, and have A string mail.company.com

This error have when i try to redirect admin mail to external mail...

How i can fix it?