email - Yahoo Domain Keys setup, getting dkim=permerror (no key)

I'm working on getting DKIM installed on my outgoing mail server, to help my email deliverability to my Yahoo clients (all legit emails, etc, no spamming).

I've got DKIM-Signature: and DomainKey-Signature: headers being generated, but a test mailer to my Yahoo account had this line in the headers:

Authentication-Results: mta250.mail.re2.yahoo.com from=example.com;

domainkeys=permerror (no key); from=example.com; dkim=permerror (no
key)

Any ideas what I may have missed?

Answer

You do not have the proper dns records set up.

You can test it youself with policy checker and selector checker.
Here is a good tutorial for setting the right records.
and also and online form for doing the same.

It seems that you have SPF records. You should definitely remove them!
Here is a case against spf.