If your emails are landing in spam or failing authentication, DKIM is often the problem.
DKIM (DomainKeys Identified Mail) is one of the core mechanisms used to verify that an email is legitimate and hasn’t been modified. But when it’s misconfigured, it can silently break your email deliverability.
In this post, I’ll show you what a DKIM record looks like, how to read it, and how to fix common issues.
A DKIM record is a DNS TXT record that contains a public key used to verify email signatures.
When an email is sent, it is signed with a private key. The receiving server then looks up the public key in DNS and verifies the signature.
If everything matches → the email is trusted
If not → it may be rejected or marked as spam
DKIM record example
A typical DKIM record looks like this:
v=DKIM1; k=rsa; p=MIIBIjANBgkqh...
Here’s what each part means:
- v=DKIM1 → DKIM version
- k=rsa → encryption type
- p= → public key used for verification
The public key is usually long and generated by your email provider.
Where DKIM records are stored
DKIM records are not placed on the root domain.
_They follow this structure:
_
selector._domainkey.yourdomain.com
The selector is provided by your email service (for example Google or Microsoft). It helps the receiving server find the correct key.
Common DKIM mistakes:
- Even when DKIM is set up, errors are very common.
- Missing selector
- If the selector doesn’t exist in DNS, DKIM will fail.
- Incorrect public key
- If the key is truncated or malformed, verification fails.
- Mismatch between sender and DNS
If your email service signs emails with a selector that doesn’t match your DNS record, DKIM breaks.
DNS propagation delay
Changes may take time to become visible globally.
How to check your DKIM record
Instead of manually checking DNS, you can use a tool to instantly validate your setup.
You can test your DKIM configuration here:
https://emaildnscheck.com/dkim/dkim-record-example
It helps you detect:
- missing records
- invalid keys
- selector issues
- configuration errors
Why DKIM matters
**
DKIM is critical for:
- email deliverability
- preventing spoofing
- passing DMARC checks
- building trust with email providers
Without DKIM, your emails are much more likely to fail authentication.
Final thoughts
DKIM might look complicated at first, but once you understand how selectors and keys work, it becomes much easier to troubleshoot.
If you send emails from your domain, make sure your DKIM record is correctly configured — it’s essential for getting your emails into the inbox.