I have built a new Zimbra server .
Added in my domain and users. Receiving emails is no problem.
But sending to extrernal email addresses, even from webmail gives me something like :
Mar 22 03:03:39 z1 postfix/smtpd: NOQUEUE: reject: RCPT from myhost.mydomain.com[xxx.xxx.xxx.xxx]: 554 5.7.1 <email@example.com>: Relay access denied;
Can anyone help with this please?