DKIM key at {selector} uses an unrecognised algorithm

What it means

k=the offending value at selector1 is not an algorithm verifiers implement. The key is ignored and the signature fails.

How to fix it

Publish the key as k=rsa, or k=ed25519 if your provider supports it.

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 3.6.1. 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

• No DKIM key found at the usual selectors
• No DKIM key at the selector you gave
• DKIM key at {selector} has been revoked
• DKIM key at {selector} is below the minimum size
• DKIM key at {selector} is only 1024 bits
• DKIM key at {selector} is restricted to SHA-1