Postfix acting like an open relay for domain mailboxes

EDIT: reading that reject_unverified_sender could cause blacklisting i've removed id, and now the problem is back

I think i've resolved this using this restrictions:

smtpd_client_restrictions =  permit_sasl_authenticated, permit_mynetworks
#smtpd_helo_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, check_helo_access pcre:/etc/postfix/helo_access.pcre
smtpd_sender_restrictions = permit_sasl_authenticated, reject_unverified_sender, reject_sender_login_mismatch, reject_unknown_sender_domain, reject_non_fqdn_sender, reject_unlisted_sender, reject_unauth_destination, permit_mynetworks
smtpd_recipient_restrictions = permit_sasl_authenticated, reject_unauth_destination

the option i was missing was reject_unverified_sender, i've added after permit_sasl_authenticated so i can still send mail with the aliases.