There are lots of undelivered outgoing emails on the Plesk server. It is not possible to send mail and messages get stuck in the mail queue.
The following errors are logged in
postfix/smtp: connect to example.com[203.0.113.2]:587: Invalid argument
postfix/smtp: 8A0FA1D2090C: [email protected], relay=none, delay=470, delays=470/0.01/0.16/0, dsn=4.4.1, status=deferred (connect to example.com[203.0.113.2]:587:
postfix/qmgr: warning: connect to transport private/203.0.113.2-: Connection refused
postfix/error: 0A1322CF16C: [email protected], relay=none, delay=0.07, delays=0.03/0.01/0/0.02, dsn=4.3.0, status=deferred (mail transport unavailable)
Postfix is misconfigured.
Connect to the server via SSH.
If there are no custom settings in Postfix’s configuration, execute
# plesk sbin mchk –without-spam
If there are some custom settings and the issue should be resolved more accurately, verify the following:
Transport settings are set as below:
# postconf -n | grep -i transport
sender_dependent_default_transport_maps = hash:/var/spool/postfix/plesk/sdd_transport_maps
transport_maps = , hash:/var/spool/postfix/plesk/transport
virtual_transport = plesk_virtual
Transport may be defined in
sender_dependent_default_transport_mapif Send from domain IP addresses option is set in Tools & Settings > Mail Server Settings:
# postmap -s /var/spool/postfix/plesk/sdd_transport_maps
Note: 203.0.113.x should be replaced with the server’s IP addresses.
If so, the entries from
sdd_transport_mapsare defined in the first column of
smtp_bind_addressis an optional numerical network address that the Postfix SMTP client should bind to when making an IPv4 connection.
# grep “smtp_bind_address” /etc/postfix/master.cf
plesk-203.0.113.2- unix – n n – – smtp -o smtp_bind_address=203.0.113.2 -o smtp_bind_address6= -o smtp_address_preference=ipv4
plesk-203.0.113.3- unix – n n – – smtp -o smtp_bind_address=203.0.113.3 -o smtp_bind_address6= -o smtp_address_preference=ipv4
To be able to connect, smtp_bind_address needs to be defined as mentioned in the mynetworks section and the binding name should be the same as defined in
# postconf mynetworks
mynetworks = 127.0.0.0/8 [::1]/128 203.0.113.2/32, 203.0.113.3/32
Starting from Plesk 12, it should be empty:
# postconf mynetworks
unless there are white-listed IP addresses in Plesk > Tools & Settings > Mail Server Settings > White List tab. If so, they will be added to
Restart the service:
# service postfix restart