What should I do if my email campaign is failing spam filter tests for old Outlook versions?
Summary
What email marketers say13Marketer opinions
Email marketer from Mailjet shares the importance of setting up email authentication protocols (SPF, DKIM, DMARC) to improve deliverability and avoid spam filters. Missing authentication can be a red flag for older email clients.
Email marketer from HubSpot shares that maintaining a good sender reputation is crucial for email deliverability. Factors like sending volume, spam complaints, and bounce rates affect your reputation.
Email marketer from Email Geeks shares an experience where a client's "All Natural Chicken" sale item caused spam filter failures, and they resolved it by using an image of the text instead of actual text.
Email marketer from EmailOnAcid responds that Outlook's rendering engine can cause display issues with HTML emails. They suggest using tables for layout and avoiding complex CSS.
Email marketer from Stack Overflow recommends optimizing images to reduce file size and ensuring proper alt text is included. Large images or missing alt text can trigger spam filters.
Email marketer from Email Marketing Forum stresses the importance of maintaining a clean email list. Sending to inactive or invalid addresses can harm your sender reputation and trigger spam filters.
Email marketer from Campaign Monitor explains that including Javascript in your emails is a bad practice and will almost guarantee emails are marked as spam as it opens up security issues.
Email marketer from Email Geeks suggests checking analytics to assess the relevance of old Outlook clients in the recipient list and mentions that fixing the issue might not be worth the effort depending on the footprint of those mail clients, adding most recipients are probably on web client and not fat clients.
Email marketer from Sendinblue explains that using spam trigger words in your email content can increase the likelihood of being filtered. They advise avoiding words like 'free,' 'guarantee,' or excessive use of exclamation points.
Email marketer from Email Geeks asks if the campaign is failing a test or going to spam, suggesting testing tools are often inaccurate compared to sending to a mailbox at the MBP of interest.
Email marketer from Reddit explains that using outdated HTML and CSS practices can cause issues with older versions of Outlook, suggesting using inline CSS and table-based layouts.
Email marketer from Litmus explains that previewing and testing your emails in different versions of Outlook is essential to ensure correct rendering and avoid triggering spam filters. They provide tools for email testing.
Email marketer from GlockApps explains that using email testing tools can help identify issues that cause emails to land in the spam folder, including problems specific to older Outlook versions.
What the experts say2Expert opinions
Expert from Word to the Wise (Laura Atkins) shares that while email authentication (SPF, DKIM, DMARC) is critical for modern email deliverability, older email clients may not fully support these protocols, and thus, a holistic approach, including content and list hygiene, is essential.
Expert from Spamresource explains that older versions of Outlook use the Word rendering engine, which has limited CSS support, and can be triggered as spam. They recommend using inline styles and testing with tools like Litmus or Email on Acid.
What the documentation says5Technical articles
Documentation from DKIM.org describes DKIM and the signing of emails to improve email authentication.
Documentation from DMARC.org describes DMARC and its role in email authentication. Implementing DMARC helps protect your domain from spoofing and phishing attacks, improving deliverability.
Documentation from Microsoft Support explains that users can adjust the level of junk email protection in Outlook, from 'No Automatic Filtering' to 'High,' which could impact whether emails are classified as spam.
Documentation from Spamhaus explains that getting on their blocklist can cause deliverability issues. They suggest checking your IP address against their blocklist and following their removal process if listed.
Documentation from RFC Editor details the standards for SMTP, which email servers must adhere to. Deviation from these standards can result in emails being flagged as spam.