I've been reading through the post.
I've followed the solution and it seems to be working until i sent a mail from my gmail account. the autoresponder tried to respond but since it wasn't local mail it had to go through my smtp relay and it got rejected because it's being sent as email@example.com
in instead of from firstname.lastname@example.org
. here's the last maillog so you could get a better idea.
Jul 22 21:13:35 srv-mkna01 postfix/smtp: C297B16DB9A: to=<email@example.com>, relay=smtp.*****[*****]:25, delay=3.9, delays=0.41/0.03/3/0.41, dsn=4.1.8, status=deferred (host smtp.****[****] said: 450 4.1.8 <web1_editorial@server01.****>: Sender address rejected: Domain not found (in reply to MAIL FROM command))
basically it's sending mail to non local addresses using a local user instead of the actual email address and it's being rejected by my smtp relay because the domain isn't fully qualified.
any help would be appreciated.