ConvertKit sends both marketing campaigns and automated emails (welcome sequences, course notifications, product launches). If these land in the spam folder, you lose engagement and revenue. The fix is usually a DNS record, not an email app.
ConvertKit sends email on your behalf using your domain (or a subdomain you set up). But the receiving mail server does not trust your domain by default. It checks your DNS records to verify the email is legitimate.
When a subscriber receives an email from yourdomain.com sent by ConvertKit, Gmail and Outlook check your domain's DNS records. If the records are missing or misconfigured, the email gets flagged as suspicious and filtered to spam.
The frustrating part: ConvertKit's dashboard shows "delivered." The email reached the mail server. It just did not reach the inbox. You have zero opens and no idea why.
Here is what the receiving mail server checks, in order:
Any one of these can break your deliverability. Most ConvertKit users have at least one missing or misconfigured.
You do not need to run dig commands by hand. Inboxproof checks all 6 records in about 30 seconds. You type in your domain, it queries your live DNS, and gives you a score plus the exact records to fix. No account, no setup, nothing to install.
The report is public and shareable, which is handy when you need to send the findings to whoever manages your DNS (your developer, your agency, your ConvertKit setup).
Many ConvertKit users use a custom domain for their website but send email from a different domain (e.g., yourdomain.com for the site, yourdomain-mail.com for email). The receiving server checks the domain in the From: header, not the domain in the URL. If your From: header says yourdomain.com but your SPF record is on yourdomain-mail.com, the email fails SPF.
Fix: make sure the domain in your From: header matches the domain with the SPF, DKIM, and DMARC records.
ConvertKit uses a specific domain include for SPF. If your SPF record does not include include:kit.com (or the specific ConvertKit sending domain you are using), the email fails SPF. Check your ConvertKit sending settings to find the exact include you need.
Fix: add the ConvertKit include to your SPF record. If you have multiple includes, make sure the total SPF lookup count stays under 10.
ConvertKit uses a specific DKIM selector. If your DKIM record is missing or the selector does not match what ConvertKit expects, the email fails DKIM. Check your ConvertKit sending settings for the current DKIM selector and make sure it is in your DNS.
Fix: add the DKIM record with the correct selector to your DNS. The record type is TXT, and the name is the selector followed by a dot and your domain.
Gmail has been enforcing DMARC more strictly since early 2024. A domain with no DMARC record, or one set to p=none, is treated as unauthenticated. Gmail filters these emails more aggressively. Set your DMARC record to at least p=quarantine, and ideally p=reject once you are confident your SPF and DKIM are correct.
Fix: add a DMARC record with p=quarantine or p=reject to your DNS. Start with p=quarantine, monitor your DMARC reports, and move to p=reject once you are confident.
If you use ConvertKit for marketing email and a different provider for transactional email (e.g., Postmark for order confirmations), both need to be in your SPF record. Missing one means emails from that provider fail SPF. Check every service that sends email on your behalf.
Fix: make sure all sending services are included in your SPF record. If you have more than 10 includes, consider using a separate domain for one of the services.
Fixing the records is the first step. But records break. Your email provider changes something. Your DNS provider expires a record. A new include gets added. You do not get an email when this happens. You find out when a subscriber says "I never got the welcome email."
Inboxproof Pro monitors all 6 records daily and emails you the moment one breaks, expires, or changes. $29/month for up to 5 domains. For an agency managing multiple clients, the Agency plan covers up to 25 domains for $99/month.
If any of these are missing, run a free audit and get the exact record values to add. Takes 30 seconds. No account needed.
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Run my free auditAudited by Inboxproof · live DNS checks · privacy