Something

May 25 10:44:04 as postfix/smtpd[3958]: NOQUEUE: reject: RCPT from [my ip]: 553 <hax@domain.com>: Sender address rejected: not owned by user hax@domain.com; from=<hax@domain.com> to=<hax@domain.com> proto=ESMTP helo=<[192.168.1.100]>

smtpd_sasl_application_name = smtpd
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain = $myhostname
broken_sasl_auth_clients = yes

smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination
smtpd_sender_restrictions = reject_sender_login_mismatch  #<--- this causes the above error