Plesk server notifications are sent without a DKIM signature, even if the Plesk domain is configured to be a mail server, and even if DKIM is configured for it.

This is done, at the same time Fail2Ban or server PHPMailers emails sent via Amazon webmail /SMTP get signed.

The absence of DKIM signature, is considered by me as a Plesk BUG, as it not being on some emails, harms the user, preventing implementation of a strict DMARC policy, due to the absence of DKIM on some emails sent to outside servers.

I find the as a Plesk BUG.

Hello, I have been able to get DKIM signing of Plesk notifications working on Plesk Obsidian 18.0.49+ (CentOs 7.9) with the following steps (maybe Plesk could create a support article to cover this?):

Ensure that "Allow signing outgoing mail" is checked in Tools & Settings > Mail Server Settings.

Ensure that you have a full hostname in Tools & Settings > Server Settings, e.g. myserver.example.com. This hostname must be resolvable by public DNS. If your server host does not automatically give you a hostname with your server, or you want to use a custom vanity hostname, you may need to set up a PTR record with them for reverse DNS.

Next, if one does not already exist, create a Plesk subscription and domain identical to the full hostname of the server, e.g. myserver.example.com. And in Mail Settings for that domain check 'Use DKIM spam protection system to sign outgoing email messages' and Apply. If you use external DNS, click on 'How to configure external DNS' and use this info to update your external DNS.

In Panel.ini Editor (Plesk Extension) add:

[notification]
senderAddress=no-reply@myserver.example.com

Obviously after the @ should be identical to the full hostname of your server.

Wait for DNS to fully propagate your server hostname and domainkey before checking the email headers of Plesk notifications. After that my emails were signed and confirmed by Microsoft 365 and SpamAssassin in the message headers as valid.

If it does not work first time, it may be necessary to go to the domain's Mail Settings again: uncheck DKIM, Apply, recheck DKIM, Apply (a new public key is generated for DNS, so update external DNS if in use).

Any questions - I might not get notified here, so reply at https://talk.plesk.com/threads/outgoing-email-messages-not-dkim-signed-when-enabled-for-a-domain-and-in-server-settings.368888/

Plesk email notifications to the administrator's email address get into Spam folder at public email providers because they are not protected by SPF, DMARC or DKIM anti-spam methods.

It is required to enhance the Plesk notification system so that Plesk email notifications are treated as legitimate email messages by the Internet email system.