The server is saturated with spam. There are many messages in the queue. Mail is sent slowly.
Often spammers using non-existing mail addresses as destination. In such cases it's recommended to check that all domains have the option What to do with mail sent to nonexistent users set to Reject and not to forward. (click on the image below to get an example)
In order to change this setting for all domains on mail server as follows:
Find the ID of the node at
Hosting Provider CP > Infrastructure > Service Nodes(for example,
- Login to PA Management node as
Get ServiceNodeId by following query:
[root@cp ~]# mysql -uadmin -p`cat /etc/psa/.psa.shadow` psa -Ne "select id from ServiceNodes where externalId=27;" +----+ | 17 | +----+
Generate list for the service node ID 27 (ID 17 in
[root@cp ~]# mysql -uadmin -p`cat /etc/psa/.psa.shadow` psa -sNe "SELECT name FROM domains WHERE parentDomainId = 0 AND id IN (SELECT dom_id FROM DomainServices WHERE type='mail' AND ipCollectionId IN (SELECT ipCollectionId FROM IpAddressesCollections WHERE ipAddressId IN (SELECT id FROM IP_Addresses WHERE serviceNodeId = 17)))" > mail01_domains.txt
serviceNodeId = 17id of mail service node, from step 3.
set_mail_opt.shscript with following content:
#!/bin/bash while read dom; do /usr/local/psa/bin/subscription_settings -u $dom -no_usr reject done < $1
Add execution permission for
[root@cp ~]# chmod 0744 set_mail_opt.sh
Now you can apply mail settings with the script as follows:
# ./set_mail_opt.sh mail01_domains.txt
mail01_domains.txt- is the list of domain with Mail Hosting on
Next step is to check that all the IP addresses and networks in the white lists are reliable and familiar to you under
Hosting Provider CP > Infrastructure > Service Nodes > mail service node > Mail Server Settings > White List. Make sure that
SMTP authorization is enabled, otherwise server will act as
open relay, i.e. allows anyone on the Internet to send e-mail through it.
Also, it's recommended to enable SpamAssassin filter on the server-wide level under
Hosting Provider CP > Infrastructure > Service Nodes > mail service node > Spam Filter Settings. In order to enable SpamAssassin by the default please check How to enable Spamassassin by default on mail accounts?
You can also apply the solution from another article, which describes the procedure of discovering which domains are sending mail through PHP scripts in case of using Postfix.
Note: In case of using Plesk Automation, all steps from #114845 article should be applied on Postfix service node and changes must be reverted back as soon as spam source will be identified.