Postfix+RoundCube邮件服务器无法收发邮件，SMTP 451配置错误排查求助

各位大佬好，我搭建的Postfix+RoundCube邮件服务器现在遇到了麻烦，收发邮件时触发SMTP 451错误，折腾了好一阵没找到问题根源，麻烦帮忙看看哪里配置出问题了？

具体报错信息 #

SMTP Error (451): Failed to add recipient "xxx@xxx" (4.3.5 Server configuration error).

系统日志记录 #

sv2 postfix/submission/smtpd[21621]: NOQUEUE: reject: RCPT from unknown[185.107.56.150]: 451 4.3.5 Server configuration error;

我已经检查了/etc/postfix/main.cf和master.cf的配置，内容如下：

/etc/postfix/main.cf 配置 #

readme_directory = /usr/share/doc/postfix-2.10.1/README_FILES

transport_maps = ldap:/etc/postfix/ldap/transport_maps.cf, hash:/etc/postfix/transport

#content_filter = smtp-amavis:[127.0.0.1]:10024

recipient_delimiter = +

smtpd_tls_key_file = /etc/pki/tls/private/localhost.pem

smtpd_sender_login_maps = $local_recipient_maps

local_recipient_maps = ldap:/etc/postfix/ldap/local_recipient_maps.cf

virtual_alias_maps = $alias_maps, ldap:/etc/postfix/ldap/virtual_alias_maps.cf, ldap:/etc/postfix/ldap/virtual_alias_maps_mailforwarding.cf, ldap:/etc/postfix/ldap/virtual_alias_maps_sharedfolders.cf, ldap:/etc/postfix/ldap/mailenabled_distgroups.cf, ldap:/etc/postfix/ldap/mailenabled_dynamic_distgroups.cf

submission_sender_restrictions = reject_non_fqdn_sender, check_policy_service unix:private/submission_policy,permit_sasl_authenticated, reject

submission_recipient_restrictions = check_policy_service unix:private/submission_policy, permit_sasl_authenticated, reject

disable_vrfy_command = yes

smtpd_helo_required = yes

# config ngay 17-04-2019-------------------

smtpd_helo_restrictions = permit_mynetworks,

permit_sasl_authenticated,

#reject_unknown_helo_hostname

#reject_non_fqdn_hostname,

#reject_invalid_hostname,

permit

smtpd_recipient_restrictions = permit_sasl_authenticated #reject_invalid_hostname # reject_non_fqdn_hostname # reject_non_fqdn_sender reject_non_fqdn_recipient # reject_unknown_sender_domain reject_unknown_recipient_domain permit_mynetworks # reject_rbl_client list.dsbl.org reject_rbl_client sbl.spamhaus.org reject_rbl_client bl.spamcop.net reject_rbl_client cbl.abuseat.org # reject_rbl_client dul.dnsbl.sorbs.net check_policy_service unix:private/recipient_policy_incoming permit #reject_invalid_hostname # reject_non_fqdn_hostname # reject_non_fqdn_sender # reject_unknown_sender_domain # reject_rbl_client list.dsbl.org # reject_rbl_client dul.dnsbl.sorbs.net #reject_invalid_hostname # reject_non_fqdn_hostname # reject_non_fqdn_sender # reject_unknown_sender_domain # reject_rbl_client list.dsbl.org # reject_rbl_client dul.dnsbl.sorbs.net #reject_invalid_hostname # reject_non_fqdn_hostname # reject_non_fqdn_sender # reject_unknown_sender_domain # reject_rbl_client list.dsbl.org # reject_rbl_client dul.dnsbl.sorbs.net #reject_invalid_hostname # reject_non_fqdn_hostname # reject_non_fqdn_sender # reject_unknown_sender_domain # reject_rbl_client list.dsbl.org # reject_rbl_client dul.dnsbl.sorbs.net #reject_invalid_hostname # reject_non_fqdn_hostname # reject_non_fqdn_sender # reject_unknown_sender_domain # reject_rbl_client list.dsbl.org # reject_rbl_client dul.dnsbl.sorbs.net #reject_invalid_hostname # reject_non_fqdn_hostname # reject_non_fqdn_sender # reject_unknown_sender_domain # reject_rbl_client list.dsbl.org # reject_rbl_client dul.dnsbl.sorbs.net

#reject_invalid_hostname,

# reject_non_fqdn_hostname,

# reject_non_fqdn_sender,

# reject_unknown_sender_domain,

# reject_rbl_client list.dsbl.org,

# reject_rbl_client dul.dnsbl.sorbs.net,

smtpd_error_sleep_time = 300s

smtpd_soft_error_limit = 10

smtpd_hard_error_limit = 20

submission_data_restrictions = check_policy_service unix:private/submission_policy

smtpd_tls_cert_file = /etc/pki/tls/private/localhost.pem

smtpd_tls_security_level = may

smtpd_relay_restrictions = yes

#message_size_limit = 204800000#mailbox_size_limit = 204800000

message_size_limit = 0

mailbox_size_limit = 0

virtual_mailbox_limit = 204800000

smtpd_client_message_rate_limit =5

smtpd_client_connection_count_limit = 40

smtpd_client_connection_rate_limit = 180

smtpd_client_new_tls_session_rate_limit = 180

smtp_destination_concurrency_limit = 2

smtp_destination_rate_delay = 1s

smtp_extra_recipient_limit = 10

relayhost = [auth.netnam.vn]:25

smtp_sasl_auth_enable = yes

smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd

smtp_sasl_security_options = noanonymous

smtp_sasl_tls_security_options = noanonymous

smtp_sasl_mechanism_filter = plain

smtpd_relay_restrictions = yes

header_checks = regexp:/etc/postfix/header_checks

/etc/postfix/master.cf 配置 #

submission          inet        n       -       n       -       -       smtpd

-o cleanup_service_name=cleanup_submission

-o syslog_name=postfix/submission

-o smtpd_tls_security_level=encrypt

-o smtpd_sasl_auth_enable=yes

-o smtpd_sasl_authenticated_header=yes

-o smtpd_client_restrictions=permit_sasl_authenticated,reject

-o smtpd_data_restrictions=$submission_data_restrictions

-o smtpd_recipient_restrictions=$submission_recipient_restrictions

-o smtpd_sender_restrictions=$submission_sender_restrictions

-o header_checks=regexp:/etc/postfix/header_checks

smtps               inet        n       -       n       -       -       smtpd

-o syslog_name=postfix/smtps

#    -o smtpd_tls_wrappermode=yes

-o smtpd_sasl_auth_enable=yes

-o smtpd_client_restrictions=permit_sasl_authenticated,reject

-o milter_macro_daemon_name=ORIGINATING

备注：内容来源于stack exchange，提问作者KML