DKIM Signing question.

[cpulove]

I use a Plesk Server as my Mailserver and a PMG.
I had the problem today, that my outgoing e-mails had double DKIM signing.
I guess they where signed by plesk and by pmg too, which resulted in this problem, with two DKIM keys in the e-mail header.

What is the best strategie to avoid signing problems? I deleted all the domains from the domain signing under DKIM in PMG.
Now only plesk signs outgoing mails. So far so good, but https://maileroo.com/mail-tester/ still gives me a warning about a non valid DKIM.

Your email setup shows issues with DKIM signature, a passing SPF record, and a successful DMARC test. The spam analysis indicates a spam score of 0.5, which is below the required threshold. A higher score may cause deliverability issues. Additionally, your email was not found on any RBLs which is good for your email deliverability. The forward-confirmed reverse DNS test shows that your IP and hostname match, indicating a correctly configured domain. Some providers such as iCloud may reject your emails if MX records are not available. Regarding the MX records, your emails are handled by a mail server, which is ideal for deliverability.

What is best practice? Do I have to turn off DKIM signing at all, when plesk does the signing?



Or ist it better not to sign in plesk and use pmg for DKIM signing?
A plain DKIM tester states, that my plesk DKIM is valid, but maybe not after it ran through the proxmox mail gateway?