How to troubleshoot email deliverability issues with Yahoo and Rogers domains, including TSS04 user complaints and delivery time expired bounces?
Michael Ko
Co-founder & CEO, Suped
Published 18 Apr 2025
Updated 19 Aug 2025
6 min read
Email deliverability to major providers like Yahoo and its partners, such as Rogers, can be a complex challenge. Many senders encounter specific bounce codes and delivery delays that signal underlying problems. When emails fail to reach the inbox, it's crucial to understand the diagnostic messages to pinpoint the root cause and implement effective solutions.
Among the most common issues are the TSS04 user complaint deferral and the frustrating 'delivery time expired' bounce. These indicate that Yahoo (or Oath, its parent company) has temporarily blocked or outright rejected your emails. This guide will help you troubleshoot these particular issues and improve your sending reputation with these vital domains.
Understanding Yahoo and Rogers' Email Filtering
Yahoo and Rogers share a common email infrastructure, meaning issues with one often extend to the other. Their filtering systems are highly sensitive to sender reputation, content quality, and user engagement. Even slight deviations from best practices can trigger blocks or deferrals. Keeping an eye on your sender metrics is crucial.
The primary goal of Yahoo's filtering system is to protect its users from unwanted email, commonly known as spam. This is why user complaints play such a significant role in their deliverability decisions. They prioritize their users' experience, which means a clean, engaged list is paramount.
When you send emails to Yahoo or Rogers domains, their systems analyze numerous factors, including your IP reputation, domain reputation, authentication records (SPF, DKIM, DMARC), and content. Any red flags in these areas can lead to your emails being flagged or rejected.
Decoding TSS04 and User Complaints
The TSS04 diagnostic code is a clear indicator that Yahoo's (Oath's) system has temporarily deferred your messages due to a significant number of user complaints. This isn't a hard bounce, but rather a temporary block signaling that your sending practices are causing recipients to mark your emails as spam.
Even if your list appears healthy and has been mailed to for years, a sudden spike in complaints, or a gradual increase, can trigger this. The system interprets these complaints as a sign of unsolicited mail, regardless of whether recipients initially opted in. Resolving Yahoo TS-04 email delivery errors is critical for good deliverability.
Example TSS04 Bounce Messagetext
Diagnostic-Code: smtp; 421 4.7.0 [TSS04] Messages from [Your.IP.Address] temporarily deferred due to user complaints - 4.16.55.1; see https://help.yahoo.com/kb/postmaster/SLN3434.html
Understanding user complaints
User complaints (or spam reports) are a strong negative signal to Yahoo. Even a small percentage of complaints can have a disproportionate impact on your sender reputation. A high volume of complaints will quickly land your domain or IP on an internal blocklist (blacklist), making it difficult to reach the inbox. This is especially true for the Yahoo blocklists.
The temporary nature of TSS04 means Yahoo expects you to cease sending to the problematic audience or fix the underlying issue. Continuing to send will likely lead to hard blocks and more severe deliverability problems, affecting your overall domain reputation.
Addressing 'Delivery Time Expired' Bounces
A 'delivery time expired' bounce (4.4.7) typically means your Mail Transfer Agent (MTA) attempted to deliver the email for a specified period, but the receiving server (like Yahoo or Rogers) continuously deferred it. After the retry window, your MTA gives up. This is usually a secondary symptom of a primary issue, such as TSS04 deferrals, or other temporary rejections.
While this bounce isn't as specific as TSS04, it points to prolonged difficulty in delivering mail. It means that Yahoo's (or Rogers') servers consistently sent a temporary failure message (4.x.x series SMTP codes), and your system eventually stopped trying. This indicates persistent issues with your sender reputation or content, rather than a transient network problem.
Code
Meaning
Impact
4.x.x
Temporary failure (soft bounce)
Mail server will retry. Can lead to 'delivery time expired' if persistent.
5.x.x
Permanent failure (hard bounce)
Mail will not be delivered. Address should be removed.
421 4.7.0 [TSS04]
Temporarily deferred due to user complaints
Specific to Yahoo and Rogers. Strong indicator of reputation issues.
To address these, you must resolve the underlying cause of the temporary deferrals. This includes improving sender reputation, ensuring proper email authentication, and maintaining a clean, engaged mailing list. You can explore how to troubleshoot and resolve soft bounce issues with Yahoo for further guidance.
Technical and Content-Related Factors
Proper email authentication is non-negotiable for Yahoo and Rogers. This includes correctly configured SPF, DKIM, and DMARC records. If you recently changed your DKIM key, for example, from 512-bit to 1024-bit, ensure the new record is properly published and validated. A misconfigured DKIM record can lead to authentication failures, which negatively impact deliverability.
Beyond authentication, the content of your emails and your sending practices heavily influence your deliverability. If you are experiencing TSS04 errors or expired delivery times, it's essential to perform a thorough audit of your email program.
Best practices
List hygiene: Regularly clean your mailing lists to remove inactive or invalid addresses. This reduces bounces and improves engagement.
Opt-in process: Implement double opt-in to ensure recipients genuinely want your emails, reducing complaints. This helps fix Yahoo deliverability issues.
Content relevance: Send valuable and relevant content to your audience to foster engagement and prevent spam reports.
Common pitfalls
Spam traps: Sending to purchased or old lists can hit spam traps, severely damaging your reputation. Learn about how spam traps work.
Broken links/URLs:Yahoo (or other ISPs) have flagged in the past can trigger blocks. Ensure your links are clean.
Sudden volume spikes: Drastically increasing your sending volume can look suspicious to ISPs and lead to throttling or blocks.
Even with consistent mailing schedules and no apparent content changes, subtle shifts in subscriber engagement or unseen URL blocklisting can lead to issues. Continuous blocklist monitoring and DMARC monitoring are important. These provide insights into how your emails are being received and whether your authentication is passing.
Engaging with Postmasters and Recovery Steps
When you encounter persistent deliverability problems, especially with specific error codes like TSS04, contacting the ISP's postmaster team is often necessary. Yahoo offers a postmaster help form where you can submit a ticket to get more details about the issue. Be prepared to provide specific bounce messages and sending IP addresses.
Tips for postmaster engagement
Consolidate information: Gather all relevant bounce messages, sending IPs, and a brief history of your sending practices before contacting them.
Be patient: Response times can vary. Continue implementing best practices while awaiting a reply. Yahoo often recommends a 4-hour cool-off period after a temporary error.
Verify authentication: Double-check your SPF, DKIM, and DMARC records before reaching out. These are foundational. You can use our free email deliverability tester.
Recovery from deliverability issues takes time and consistent effort. Once you've identified and addressed the root cause of TSS04 or 'delivery time expired' bounces, maintain diligent list hygiene, monitor your sender reputation, and adjust your sending strategy as needed. Consistency and adherence to email sending best practices are key to long-term success with Yahoo and Rogers.
Views from the trenches
Best practices
Regularly monitor your email logs for diagnostic codes and bounce messages to catch issues early.
Implement a robust list cleaning process to remove unengaged subscribers and reduce complaint rates.
Verify all email authentication records (SPF, DKIM, DMARC) are correctly configured after any changes.
Common pitfalls
Ignoring temporary deferral messages, assuming they will resolve on their own, can lead to harder blocks.
Not thoroughly investigating the cause of user complaints, even if list size or content remains consistent.
Failing to check for blacklisted URLs in your email content, which can trigger immediate blocks.
Expert tips
If experiencing TSS04, back off sending to that segment for at least four hours as Yahoo suggests.
Actively use Yahoo's Complaint Feedback Loop to identify and remove users who complain.
If 'delivery time expired' bounces occur, understand they are often a symptom of underlying reputation issues, not just a transient network problem.
Marketer view
Marketer from Email Geeks says they were seeing issues with Yahoo and Rogers domains a couple of weeks ago, experiencing TSS04 deferrals due to user complaints and delivery time expired bounces, despite a consistent mailing schedule and content for years.
2018-11-07 - Email Geeks
Expert view
Expert from Email Geeks says that a 'delivery time expired' bounce means the sending MTA attempted delivery for a certain period before giving up, indicating persistent temporary rejections.
2018-11-07 - Email Geeks
Sustaining good deliverability
Troubleshooting email deliverability issues with Yahoo and Rogers domains requires a comprehensive approach. It involves not just understanding specific bounce codes like TSS04 or 'delivery time expired', but also diligently maintaining your sender reputation, ensuring technical compliance (authentication), and focusing on user engagement. Proactive management of your email program will help ensure your messages consistently reach their intended recipients.
Yahoo and its partners, such as 
Rogers, can be a complex challenge. Many senders encounter specific bounce codes and delivery delays that signal underlying problems. When emails fail to reach the inbox, it's crucial to understand the diagnostic messages to pinpoint the root cause and implement effective solutions.
Oath, its parent company) has temporarily blocked or outright rejected your emails. This guide will help you troubleshoot these particular issues and improve your sending reputation with these vital domains.
