DKIM is a digital signature that your email provider adds to each message you send. Receivers use it to check that the message really came from your domain and was not changed on the way.
Your email provider creates the signing keys. You publish the matching public key in your domain's DNS, following the instructions the provider gives you. A change of domain or provider usually needs a new record.
A signed message is easier for receivers to trust. Messages without a signature, or with a broken one, are more likely to end up in spam. It does not replace SPF; it adds to it.
A new provider, a changed domain or a forgotten step can leave DKIM unset. Email still goes out, but without the extra proof.
In your provider's settings, see whether DKIM is switched on. Then check that the DNS record it asks for is published.
Our free Website check looks for DKIM and reports what it found for your domain. Open Website check
Last reviewed: 2026-11-02
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