This looks like email to the user "iqbala" with an extension of
"sysadmin" using qmail's "-" as a delimiter.
> Feb 23 18:40:02 mail postfix/smtpd: NOQUEUE: reject: RCPT from remote.example.net[192.168.18.193]: 550 5.1.1 <[hidden email]>: Recipient address rejected: User unknown in local recipient table; from=<[hidden email]> to=<[hidden email]> proto=ESMTP helo=<remote.example.net>
> I am using postfix 2.6.6 on CentOS 6.7. My recipient_delimiter is `+'
> I just migrated from qmail to postfix.
> Any suggestion is appreciated.
If you've migrated from qmail, you should probably keep "-" as your
recipient delimiter to maintain as much backwards-compatible behaviour
Otherwise you'll need an explicit alias for each actively used "-"