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- Linux/BSD distribution name and version:
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====

Hi,

why email from yahoo that contains underscore cannot send to my domain but if no underscore can sending to my domain.

Jul 16 15:07:29 mail postfix/smtpd[9822]: NOQUEUE: reject: RCPT from unknown[192.168.100.1]: 450 <nurul_tjoil@yahoo.com>: Sender address rejected: undeliverable address: host mta7.am0.yahoodns.net[66.196.118.34] said: 501 Syntax error in parameters or arguments (in reply to MAIL FROM command); from=<nurul_tjoil@yahoo.com> to=<emmy@apex.com.my> proto=ESMTP helo=<milter>

example if nurultjoil@yahoo.com my domain can receive it

any idea

postconf -n

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases, hash:/var/mailman/data/aliases
append_at_myorigin = no
append_dot_mydomain = no
body_checks = regexp:/etc/postfix/body_checks
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
debug_peer_level = 2
default_destination_concurrency_limit = 10
disable_vrfy_command = yes
enable_server_options = yes
header_checks = regexp:/etc/postfix/header_checks
html_directory = no
inet_interfaces = all
invalid_hostname_reject_code = 554
local_recipient_maps = proxy:unix:passwd.byname $alias_maps
mail_owner = postfix
mailbox_size_limit = 0
mailbox_transport = cyrus
mailq_path = /usr/bin/mailq
manpage_directory = /usr/share/man
masquerade_classes = envelope_sender, header_sender, header_recipient
masquerade_domains =
masquerade_exceptions =
message_size_limit = 20971520
multi_recipient_bounce_reject_code = 554
mydestination = $myhostname,localhost.$mydomain
mydomain = apex.com.my
mydomain_fallback = localhost
myhostname = mail.apex.com.my
mynetworks = 127.0.0.0/8
mynetworks_style = host
myorigin = $mydomain
newaliases_path = /usr/bin/newaliases
non_fqdn_reject_code = 554
owner_request_special = no
queue_directory = /private/var/spool/postfix
readme_directory = /usr/share/doc/postfix
recipient_delimiter = +
relay_domains_reject_code = 554
relay_recipient_maps = hash:/etc/postfix/relay_recipients
sample_directory = /usr/share/doc/postfix/examples
sendmail_path = /usr/sbin/sendmail
setgid_group = postdrop
smtp_always_send_ehlo = yes
smtp_bind_address =
smtpd_client_restrictions = permit_mynetworks,          permit_sasl_authenticated,          check_client_access hash:/etc/postfix/smtpdreject,          check_client_access hash:/etc/postfix/access,       check_client_access hash:/etc/postfix/sender_access,          reject_rbl_client zen.spamhaus.org,       reject_rbl_client 127.0.0.2-8
smtpd_data_restrictions = permit_mynetworks, reject_unauth_pipelining
smtpd_delay_reject = yes
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks,           permit_sasl_authenticated,          reject_invalid_hostname,       regexp:/etc/postfix/helo.regexp,          check_helo_access hash:/etc/postfix/helo_access
smtpd_pw_server_security_options = login,cram-md5,plain,gssapi
smtpd_recipient_limit = 498
smtpd_recipient_restrictions = reject_unknown_sender_domain,        reject_unknown_recipient_domain,        reject_non_fqdn_sender,        reject_non_fqdn_recipient,        reject_unlisted_recipient,             permit_mynetworks,            permit_sasl_authenticated,            reject_invalid_hostname,            reject_unknown_recipient_domain,        reject_multi_recipient_bounce,        reject_unauth_pipelining,            check_client_access cidr:/etc/postfix/mynetworks,             check_sender_access hash:/etc/postfix/sender_access,        check_client_access hash:/etc/postfix/client_access,         reject_unauth_destination,            reject_rbl_client multi.uribl.com,            reject_rbl_client dsn.rfc-ignorant.org,        reject_rbl_client list.dsbl.org,        reject_rbl_client sbl-xbl.spamhaus.org,            reject_rbl_client dul.dnsbl.sorbs.net,            reject_rbl_client bl.spamcop.net,            reject_rbl_client dnsbl.sorbs.net,            reject_rbl_client cbl.abuseat.org,            reject_rbl_client ix.dnsbl.manitu.net,            reject_rbl_client combined.rbl.msrbl.net,            reject_rbl_client rabl.nuclearelephant.com,            reject_rbl_client zen.spamhaus.org
smtpd_reject_unlisted_recipient = yes
smtpd_restriction_classes = check_for_valid_sender
smtpd_sasl_application_name = smtpd
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain =
smtpd_sasl_security_options = noanonymous
smtpd_sender_login_maps = hash:/etc/postfix/virtual
smtpd_sender_restrictions = permit_mynetworks,           permit_sasl_authenticated,       reject_invalid_hostname,       reject_unauth_destination,          check_sender_access hash:/etc/postfix/sender_access,        check_sender_access hash:/etc/postfix/smtpdreject,           reject_unauth_pipelining,       reject_unknown_sender_domain,       reject_non_fqdn_sender,       reject_rbl_client 127.0.0.2-8
smtpd_tls_auth_only = no
smtpd_tls_cert_file = /etc/certificates/Default.crt
smtpd_tls_key_file = /etc/certificates/Default.key
smtpd_use_pw_server = yes
smtpd_use_tls = no
strict_rfc821_envelopes = yes
unknown_address_reject_code = 554
unknown_client_reject_code = 554
unknown_hostname_reject_code = 554
unknown_local_recipient_reject_code = 554
unknown_relay_recipient_reject_code = 554
virtual_alias_maps = hash:/etc/postfix/virtual
virtual_mailbox_domains = hash:/etc/postfix/virtual_domains
virtual_transport = lmtp:unix:/var/imap/socket/lmtp
mail:/Users/admin root#