No DKIM key at the selector you gave
URGENTWhat it means
Nothing is published at selector1._domainkey.example.com. Mail signed with that selector cannot be verified, which costs you deliverability and removes one of the two ways DMARC can pass.
How to fix it
Publish the public key your provider gave you at selector1._domainkey.example.com, or correct the selector name.
Check your own domain
This page describes the condition. To find out whether your domain has it, run the DKIM test or the full checkup, which examines every record at once.
Understand it properly
This page covers one condition. For the whole picture, What is DKIM, selectors and key strength, or start at the Health Library.
Where this comes from
We judge this against RFC 6376 section 3.6.2.1. Every finding on this site cites the specification behind it so you can check the work rather than take our word for it.
Other DKIM conditions
DKIM_RECORD_MISSING
Every fix on this site is yours to implement. If you would rather someone did it, I take this work directly.