Why custom domain emails land in spam after DMARC changes?

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What you are probably seeing

Outbound messages sent from your custom domain show high bounce rates or vanish entirely, while incoming replies still arrive normally.

Internal testing reveals that emails from your team account are blocked or flagged by clients because the sending authentication tags do not match.

Why it happens

Mail providers verify that the sending server has permission to use your domain by checking DKIM signatures and DMARC policies.

When these DNS records are missing or misconfigured, the receiving server rejects the message as spoofing even if the sender is legitimate.

What changed recently

Step by step

1. Log in to your DNS provider and confirm that a valid DKIM record exists for the sending subdomain.

2. Create a DMARC record starting with a monitoring policy to log failures without blocking delivery.

3. Test outgoing messages using an email analysis tool to verify that both DKIM and DMARC checks pass.

4. Update the DMARC record to reject policy once monitoring confirms that all legitimate sources pass authentication.

5. Monitor your provider dashboards for one week to ensure that no valid email sources are blocked by the new settings.

Ways to go further

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