What are TSS04 errors and how do I fix them?
Summary
What email marketers say7Marketer opinions
Email marketer from Stack Overflow user responds that Yahoo's TSS04 errors often mean the sending IP has been flagged. They suggest checking the IP against blocklists and working with your ESP to improve IP reputation.
Email marketer from Gmass Blog states that TSS04 errors could indicate issues with your email content triggering spam filters. They recommend A/B testing different subject lines and content to identify and remove potentially problematic elements.
Email marketer from Mailjet explains that TSS04 errors are generally related to sending reputation and volume. They recommend warming up your IP address, ensuring your sending lists are clean and engaged, and carefully monitoring bounce rates and complaint rates.
Email marketer from Campaign Monitor suggests that TSS04 errors could arise from inconsistent sending patterns. They advise maintaining a regular sending schedule to establish a predictable reputation with ISPs.
Email marketer from Litmus Blog shares that TSS04 errors highlight the importance of email authentication. They recommend strictly adhering to authentication best practices, including setting up SPF, DKIM and DMARC.
Email marketer from Reddit user shares that TSS04 errors often arise when sending to Yahoo addresses. They recommend segmenting Yahoo recipients and sending smaller batches to avoid triggering spam filters.
Email marketer from Email On Acid Blog suggests that TSS04 errors can be related to poor list hygiene. They advise regularly cleaning your email lists to remove inactive subscribers and hard bounces to maintain a good sender reputation.
What the experts say3Expert opinions
Expert from Email Geeks responds to a question about Yahoo and suggests waiting 4 hours and retrying due to potential TSS04 errors.
Expert from Spam Resource, John Levine, explains that Yahoo! Mail blocking, including issues that might lead to TSS04-like errors, is often related to content filtering and encourages senders to test their messages with services like SpamAssassin to identify potential issues before sending.
Expert from Word to the Wise, Laura Atkins, explains the importance of feedback loops. While not directly addressing TSS04 errors, understanding and implementing feedback loops is crucial for managing sender reputation and identifying potential issues that could lead to blocking or deferral issues like TSS04. This allows senders to proactively address complaints and improve their practices.
What the documentation says4Technical articles
Documentation from Postmark explains that while they don't specifically list TSS04, temporary deferrals from major providers often mean examining content for anything that might be flagged as spam, reviewing your sending volume and cadence, and ensuring compliance with all email regulations.
Documentation from SendGrid explains TSS04 as a temporary deferral from Yahoo Mail due to reputation concerns. It suggests monitoring sending reputation metrics in SendGrid, improving email authentication (SPF/DKIM/DMARC), and ensuring a clean email list with engaged subscribers.
Documentation from SparkPost explains that TSS04 errors from Yahoo indicate a temporary block based on their assessment of the email's content or the sender's reputation. Suggests reviewing content for spam triggers, checking IP and domain reputation, and throttling sending volume.
Documentation from Microsoft Support explains that TSS04 errors in Exchange Online indicate that outgoing mail is temporarily blocked due to suspected spam activity. They advise reviewing sending practices, ensuring SPF, DKIM, and DMARC records are properly configured, and contacting support if the issue persists.