Dealing with DKIM and DMARC failures in your email campaigns can be incredibly frustrating, especially when you're using a platform like ConvertKit. I've seen many marketers scratch their heads wondering why their meticulously crafted emails are not landing in the inbox as expected, often seeing those dreaded 'DKIM:FAIL' and 'DMARC:FAIL' messages in their reports.
These authentication protocols, DKIM and DMARC, are critical for verifying the legitimacy of your emails. Without them, mailbox providers, like Gmail and Yahoo, are much more likely to flag your messages as spam or reject them outright. This impacts your deliverability and, consequently, your email marketing effectiveness.
This guide will walk you through the common culprits behind DKIM and DMARC failures when sending with ConvertKit and provide actionable steps to resolve these issues, ensuring your emails reach their intended audience.
DKIM, or DomainKeys Identified Mail, uses a digital signature to verify that an email message was not altered in transit and that it originated from a legitimate sender. ConvertKit, like many ESPs, leverages underlying sending infrastructure, often SendGrid, to sign your emails with a DKIM signature. This signature is based on a public key published in your domain's DNS records.
DMARC, or Domain-based Message Authentication, Reporting, and Conformance, builds upon DKIM and SPF (Sender Policy Framework). It provides instructions to receiving mail servers on how to handle emails that fail authentication and offers a reporting mechanism. For DMARC to pass, either SPF or DKIM (or both) must pass and align with your From: domain. This alignment is crucial. If DKIM passes but the signing domain doesn't align with your email's 'From:' header, DMARC will still fail.
A common point of confusion with ConvertKit is their policy on verified sending domains. They primarily focus on verifying one sending domain per account for authentication purposes. While you can add multiple 'from' email addresses, only emails originating from the single verified domain will consistently pass DMARC checks. If you send from an unverified domain or one that doesn't align with the single signed domain, DMARC failures are likely.
Common reasons for DKIM and DMARC failures
Several factors can lead to DKIM and DMARC failures when you're sending emails through ConvertKit. Let's look at some of the most common issues I've encountered that cause these authentication problems:
Incorrect DNS records: This is often the primary culprit. Typos, missing TXT records, or incorrect values for your DKIM public key in your DNS can prevent validation. While some v= tags are automatically included, a malformed record could still cause issues.
DKIM selector issues: ConvertKit typically uses a specific DKIM selector like cka._domainkey. If this selector doesn't match what's expected or if there are conflicting records for that selector, DKIM will fail.
DMARC alignment failures: Even if DKIM passes for the technical sending domain, if that domain doesn't align with the From: header domain your recipients see, DMARC will fail. This is common when not using a custom sending domain in ConvertKit, or if you're sending from a domain that isn't the one ConvertKit verified for DMARC.
DMARC policy enforcement: If your DMARC record has a policy of p=quarantine or p=reject, any email failing DKIM or SPF alignment will be quarantined or rejected. A p=none policy will only monitor failures, not enforce action. If you're seeing failures, even with p=none, it indicates an underlying authentication issue.
It's worth noting that ConvertKit's architecture, which often relies on SendGrid for email sending, means that the technical sending domain for DKIM might sometimes be a SendGrid domain. However, DMARC requires that the domain in the From: header aligns with the authenticated domain for DMARC to pass. If you're not seeing alignment, this is a key area to investigate.
Troubleshooting DKIM and DMARC in ConvertKit
To get your ConvertKit emails authenticating correctly, I recommend a systematic approach to troubleshooting. Here are the steps I typically advise:
Verify ConvertKit's domain settings: Log into your ConvertKit account and navigate to the Email Settings or Domain Verification section. Ensure your sending domain is properly verified and authenticated. ConvertKit will provide the TXT records you need to add to your DNS.
Check your DNS records: This is where many issues arise. Double-check that the DKIM TXT record provided by ConvertKit (e.g., cka._domainkey.yourdomain.com) is exactly as specified in your DNS provider's settings. Even a single character mistake can cause a failure. Also, ensure there are no conflicting DKIM records for the same selector.
Review DMARC reports: DMARC reports provide invaluable insights into why your emails are failing authentication. They show you which emails are failing, why they are failing (DKIM or SPF), and from which sources. This data is crucial for diagnosing alignment issues.
Here’s an example of what your DKIM record might look like in your DNS settings:
Remember that DNS changes can take some time to propagate across the internet, typically a few hours, but sometimes up to 48 hours. If you've just made changes, give it some time before re-testing.
Proactive email deliverability management
While resolving immediate failures is important, adopting a proactive approach to email deliverability is key. I always stress the importance of continuous monitoring and maintenance to prevent future issues.
Consistent monitoring: Regularly check your DMARC reports. They are your best defense against hidden authentication problems or unauthorized use of your domain. You can use a DMARC monitoring service to automate this.
Domain reputation management: Authentication failures negatively impact your domain's reputation. A poor reputation can lead to emails landing in spam or being rejected, even if authentication eventually passes. Learn how to manage your email domain reputation.
Gradual DMARC policy enforcement: If you're currently at p=none, consider moving to p=quarantine and then p=reject once you're confident in your authentication setup. This protects your brand from phishing and spoofing. Here's how DMARC policies impact delivery:
Policy
Impact on email failing authentication
p=none
No action taken. Emails are delivered as usual. You receive reports on failures.
p=quarantine
Emails are sent to the recipient's spam or junk folder. You receive reports.
p=reject
Emails are blocked and not delivered at all. You receive reports on rejections.
By actively managing your DNS records, monitoring DMARC reports, and understanding ConvertKit's sending domain policies, you can significantly improve your email deliverability and ensure your messages land in the inbox, not the spam folder.
Views from the trenches
It can be frustrating when authentication issues pop up, especially with a platform that aims for simplicity. Based on insights from the community and my own experience, these issues often boil down to the specifics of DNS configuration and how ConvertKit handles sending domains.
Best practices
Always verify your sending domain within ConvertKit's settings first.
Carefully copy and paste the exact DNS records provided by ConvertKit, checking for extra spaces or characters.
Monitor your DMARC reports regularly to catch any authentication failures early.
Understand that ConvertKit typically supports one signed domain per account for full DMARC compliance.
Common pitfalls
Sending from an unverified 'From:' domain in ConvertKit, leading to DMARC alignment failures.
Typos or incomplete DNS entries for DKIM or DMARC records.
Not waiting long enough for DNS changes to propagate globally.
Assuming that a passing DKIM check means DMARC will also pass without considering alignment.
Expert tips
The `v=DKIM1` tag is standard and usually automatically included. Missing it in your manual setup can indeed cause issues. It should always be the first tag in your DKIM record.
A DMARC policy of `p=none` won't cause failures, but it won't enforce actions either. It merely monitors. To truly leverage DMARC for security, you'll want to move to `p=quarantine` or `p=reject` once your email streams are clean.
The `cka._domainkey` selector is a standard ConvertKit (SendGrid-based) selector. Ensure this is correctly published and there aren't conflicting records.
If you manage multiple domains, ConvertKit's limitation of one signed domain per account is a significant hurdle. Emails from other domains will likely fail DMARC unless explicitly configured elsewhere.
Marketer view
A marketer from Email Geeks says they found their DKIM and DMARC failing, even though local DNS checks showed the DKIM record. They noted a missing 'v' tag in their DKIM and a DMARC record without a quarantine or reject policy.
2021-01-04 - Email Geeks
Expert view
An expert from Email Geeks says ConvertKit operates on SendGrid servers and inquired about the DKIM public key selector, which was confirmed as 'cka._domainkey'.
2021-01-04 - Email Geeks
Bringing it all together
Resolving DKIM and DMARC failures in ConvertKit requires careful attention to your DNS records and an understanding of how ConvertKit handles email authentication. The primary focus should be on ensuring your DKIM record is correctly published for the designated selector (like cka._domainkey) and that your DMARC record is configured to align with your sending practices.
By systematically checking your settings, confirming domain verification within ConvertKit, and leveraging DMARC reports for insights, you can diagnose and fix most authentication issues. This ensures your emails are delivered, maintain your sender reputation, and contribute to the success of your email campaigns.
Gmail and 
Yahoo, are much more likely to flag your messages as spam or reject them outright. This impacts your deliverability and, consequently, your email marketing effectiveness.
