Why are Yahoo and AOL email engagement and delivery rates dropping?

Key findings

• Sudden drops observed: Many marketers reported a sudden and significant decrease (around 50%) in Yahoo and AOL email engagement and an increase in temporary failures and bounces starting around February 24-25, 2022.
• Error codes: Commonly reported errors include 552 1 (mailbox not found) and 554 30 (mailbox is disabled), alongside throttling errors like 421, TSS04, and TSS05. These suggest both list hygiene issues and sender reputation challenges.
• ISP denials of widespread change: Yahoo postmaster representatives stated that there were no widespread algorithm changes or periodic cleanup events, despite the collective experience of senders. They emphasized that throttling usually has specific reasons related to sender behavior.
• Reputation impacts: TSS04 and TSS05 errors indicate sender reputation issues, requiring a focus on improving sending practices rather than assuming ISP-side changes.
• New bulk sender requirements: Recent requirements from Google and Yahoo (starting February 1, 2024) demand adherence to stricter authentication, lower spam rates, and easy unsubscription, significantly impacting bulk senders.

Key considerations

• Proactive monitoring: Regularly monitor your deliverability metrics, including open rates, click-through rates, and bounce rates, to detect sudden changes indicative of underlying issues.
• Address reputation issues: If encountering TSS04/05 errors or throttling, prioritize actions to improve sender reputation, such as reducing spam complaints and maintaining a clean list.
• Engage postmaster teams: While responses may be automated, contacting ISP postmaster teams is the official channel for support when facing persistent delivery issues. You can also explore our article on why your yahoo email delivery rate decreased.
• Adhere to best practices: Ensure full compliance with bulk sender requirements, including proper authentication (SPF, DKIM, DMARC), maintaining low spam complaint rates (below 0.1%), and offering easy unsubscription options.
• Optimize sending practices: Review your sending volume and frequency. If you're experiencing throttling, consider gradually adjusting your sending speed or segmenting your audience to send to more engaged users first. For more guidance on this, see what causes a sudden drop in email open rates.

Key opinions

• Sudden performance drops: Multiple marketers observed a noticeable decline in Yahoo and AOL open rates and an increase in temporary failures for certain IPs, with issues beginning around the same specific date.
• Postmaster response frustration: Many expressed frustration over receiving generic, automated responses from Yahoo's postmaster, which typically directed them to general bulk sending best practices without specific insights into their issues.
• Shared experience: The shared experience of drastic changes in engagement or outright blocks (421/TSS04s) across different clients and mail streams led many to believe there was an underlying change on Yahoo/AOL's end.
• Impact on business: The deliverability issues significantly impacted marketers' ability to reach their audiences, leading to upset clients and a feeling of helplessness when traditional troubleshooting steps failed.

Key considerations

• Data-driven assumptions: Given the lack of specific ISP communication, marketers often rely on their data, trends, and collective experiences to infer changes in filtering algorithms. For additional insights, check out how yahoo data has changed for email marketers.
• Test and adapt: When facing issues, marketers suggested sending small test volumes to gauge deliverability improvement before resuming full sending, indicating a cautious approach to recovery.
• Community engagement: Sharing experiences within the community helps validate observations and collectively identify potential widespread issues, even when official channels are unresponsive. Understanding why your open rates are lower can be a first step.
• Focus on reputation: Even if perceived as unfair, continuing to focus on building positive sender reputation, reducing bounces, and minimizing complaints remains a critical long-term strategy.

Key opinions

• Reaction to 'bad things': Machine learning algorithms at ISPs may react to an increase in malicious activity, such as phishing or cyber warfare, by tightening filters across the board, even if not explicitly stated.
• No periodic cleanup: Yahoo (and AOL) do not have scheduled house cleaning events where inactive mailboxes are removed en masse at specific times of the year. Inactivity leading to bounces is a fluid, continuous process. More on this is available in our article why yahoo/aol email addresses bounce as disabled.
• Throttling vs. blocking: Throttling connections (e.g., TSS04 errors) is distinct from outright blocking. It typically indicates an ISP's system detecting a reason for caution, often related to sender reputation.
• Focus on reputation: TSS04/05 errors are direct indicators of sender reputation issues. The solution lies in improving sending practices, reducing complaints, and cleaning lists. You may also find our article on understanding your email domain reputation helpful.

Key considerations

• Postmaster as primary contact: For specific issues, the ISP's postmaster team remains the designated channel for investigation and assistance, even if initial responses are automated. This is outlined in Klaviyo's guidance on email deliverability monitoring.
• Transparency vs. data: While ISPs claim transparency, the practical experience for mailers often involves interpreting trends and data to understand deliverability changes, especially when direct communication is limited.
• Continuous improvement: Sustained good sending practices, including list hygiene, content relevance, and adherence to authentication standards (like SPF, DKIM, and DMARC), are essential for long-term inbox success.
• Holistic view: It's important to consider all factors, from global cyber security alerts to individual sender behavior, when diagnosing deliverability issues, as multiple elements can interact to impact performance.

Key findings

• Strict spam threshold: Gmail and Yahoo/AOL mandate bulk senders to maintain a spam rate below 0.30%, with an ideal target of 0.10%. Exceeding this can lead to significant deliverability issues.
• New sender requirements: As of February 1, 2024, new rules are enforced for bulk senders by Google and Yahoo, covering email authentication (SPF, DKIM, DMARC), spam rates, and a one-click unsubscribe option.
• Yahoo's enforcement: While Yahoo has new bulk sender requirements similar to Gmail, their enforcement has been noted as less aggressive initially, with a new Sender Hub Dashboard providing additional tools.
• Impact of spam complaints: A high percentage of consumers marking emails as spam (e.g., 19.9%) has a magnified impact on deliverability due to active implementation of new policies by major ISPs.

Key considerations

• Authentication is non-negotiable: Proper implementation of SPF, DKIM, and DMARC is fundamental. These protocols verify sender identity and are critical for avoiding deliverability issues. Read a simple guide to DMARC, SPF, and DKIM.
• Manage spam complaints: Actively work to keep spam complaint rates well below the 0.30% threshold by sending relevant content to engaged subscribers only. Our article on why your emails are going to spam provides further insight.
• Simplify unsubscription: Ensure your emails include a prominent and functional one-click unsubscribe option in the header, as this is a key compliance requirement for bulk senders.
• Leverage postmaster tools: Utilize available postmaster tools from Yahoo (and Google) to monitor sender reputation, identify issues, and access best practices guidelines. This helps diagnose and address deliverability problems proactively.