dkim fails

I'm having DKIM issues. I see a "dkim=perm_fail" in email headers on an email sent to a yahoo account. Gmail will not allow any emails to arrive saying it needs SPF and DKIM to be successful. SPF is a-aok and yahoo email acknowledges that. I create a selector in Plesk (Windows Obsidian 18.0.61...

Hi, I'm using CentOS 7 with Plesk Obsidian Web Host Edition 18.0.54 #4. I'm having a problem with DKIM only on one domain. Webmail is disabled, clients in this domain use mail clients as Outlook, Thunderbird, ... No error messages detected in /var/log/maillog related to DKIM. DKIM is enabled...