Why are my low-volume emails going to spam despite having SPF and DKIM set up?
Summary
What email marketers say10Marketer opinions
Email marketer from Stack Overflow suggests that having a missing or misconfigured reverse DNS record could be contributing to emails landing in spam, despite having SPF and DKIM records configured. A correct rDNS record helps to verify the identity of the sending server.
Email marketer from HubSpot shares that inconsistent sending patterns (e.g., sporadic emails) can negatively impact sender reputation. Maintaining a consistent sending schedule helps mailbox providers trust your emails.
Email marketer from Litmus explains that low engagement (low open rates, click rates) signals to mailbox providers that your emails are not valuable to recipients, leading to deliverability problems, even with proper authentication.
Email marketer from Reddit suggests that even with low volume, a new or shared IP address can have a poor reputation. Warming up the IP address gradually is crucial for building a good sender reputation.
Email marketer from Campaign Monitor explains that inconsistent or misleading 'From' names and email addresses can trigger spam filters. Using a recognizable name and a consistent email address that recipients can easily identify can improve deliverability.
Marketer from Email Geeks suggests setting DKIM/SPF records for the subdomain and using a reputable SMTP hosting company with a shared or private IP to resolve the email deliverability issue.
Email marketer from Email Marketing Forum suggests checking if you are enrolled in feedback loops with major ISPs. Feedback loops provide information about spam complaints, allowing you to remove complainers from your list and improve deliverability.
Email marketer from SendPulse shares that using spam trigger words, poor HTML coding, or a high image-to-text ratio can cause emails to be flagged as spam, even if SPF and DKIM are properly configured.
Email marketer from Mailjet explains that even with SPF and DKIM, a low sender reputation can cause emails to go to spam. Low engagement, inconsistent sending volume, and being marked as spam by recipients can all negatively impact sender reputation.
Email marketer from EmailOctopus explains that sending to an old or unengaged list can result in high bounce rates and spam complaints, negatively impacting deliverability even with SPF and DKIM.
What the experts say6Expert opinions
Expert from Word to the Wise explains that seed listing helps to establish a positive sending reputation, especially when starting with low volumes. It involves sending to a small, trusted group of recipients across various ISPs to monitor deliverability and identify potential issues before sending to a larger audience.
Expert from Word to the Wise explains the importance of a proper IP address set up. Steve Jones explains that if you're using a dedicated IP address, make sure it's properly warmed up and has a good reputation before sending even low volume emails.
Expert from Word to the Wise shares the importance of sending consistent email. Sending infrequently or inconsistently, even with authentication, can harm your sending reputation. Internet Service Providers (ISPs) like to see a regular pattern of email sending from a source.
Expert from Email Geeks shares that seeing the error message initially when bringing a new ESP online on a new subdomain is normal and may resolve itself over time as Gmail becomes accustomed to the emails and sees recipient engagement.
Expert from Email Geeks suggests the root cause is likely the very low volume and infrequent sending to a limited set of inboxes. They recommend having recipients pull the emails out of their spam folders and mark them as "not spam".
Expert from Spam Resource explains that DMARC policies, especially when set to 'quarantine' or 'reject', can inadvertently cause legitimate low-volume emails to be filtered as spam if there are underlying authentication issues that are not immediately apparent, such as SPF failing due to forwarding or DKIM signatures not properly aligning.
What the documentation says5Technical articles
Documentation from Google Support explains that Gmail's spam filters consider many factors, including sender reputation, authentication, email content, and user feedback. Even with authentication, if the content is similar to spam or users frequently mark emails from the sender as spam, Gmail may still filter the emails.
Documentation from Microsoft Support explains that Outlook filters consider the sender's reputation, content, and user complaints. Joining the Smart Network Data Services (SNDS) program can help monitor your IP reputation and identify potential issues.
Documentation from RFC explains that SPF only validates the sending server's IP address. If the email is forwarded or goes through multiple servers, SPF can break, leading to deliverability issues. Using SPF in conjunction with DKIM and DMARC is best practice.
Documentation from DMARC.org explains that DMARC builds upon SPF and DKIM to provide clear instructions to mailbox providers on how to handle emails that fail authentication. A DMARC policy of 'none' will not prevent emails from going to spam, while a stricter policy ('quarantine' or 'reject') will affect deliverability based on authentication results.
Documentation from IETF suggests that ensuring your email server is properly configured for IPv6, including appropriate DNS records (AAAA records), can improve deliverability as more mailbox providers are using IPv6 for email delivery.