zimbra@mail:~$ zmlocalconfig -n | grep smtpd
smtpd_recipient_restrictions = reject_non_fqdn_recipient, reject_unlisted_recipient, reject_non_fqdn_sender, permit
zimbra@mail:~$ zmlocalconfig -u smtpd_recipient_restrictions
Error: key smtpd_recipient_restrictions is not set

Please can someone help, I can't delete key but it exists...