[asantiago]

I'm looking for some advice from people with experience in email marketing and deliverability.

I've been using PMTA to send email campaigns, averaging around 200,000 emails per day to Yahoo and AOL recipients. Everything was running reasonably well, but recently I've started running into deliverability problems.

The main issues I'm seeing are TSS04 and TSS09 errors, and they've had a significant impact on my sending performance.

Has anyone else dealt with these error codes before? If so, what was the root cause in your case, and what steps did you take to improve deliverability?

 

[CoreyWilliams78]

I ran into similar deliverability issues a while back. In my case, the biggest improvement came from reviewing my mailing lists and removing inactive recipients. Better list hygiene made a noticeable difference.

 

[epalmer602]

Yahoo has become much stricter over the past couple of years. If you're sending that volume, I'd start by reviewing your sender reputation and engagement metrics before making infrastructure changes.

 

[smccarthy2231]

I haven't dealt with those exact error codes, but whenever deliverability drops, I usually check authentication first. Making sure SPF, DKIM, and DMARC are configured correctly is always a good starting point.

 

[mbrown975]

One thing that helped me was slowing down my sending volume after a reputation issue. Gradually rebuilding trust with mailbox providers worked better than continuing at full speed.

 

[JillWolfe]

Have you noticed whether the errors affect all campaigns or only certain mailing lists? That information might help narrow down the cause.

 

[sschroeder754]

I'd recommend checking your bounce logs carefully. Sometimes the error messages contain additional details that point toward the underlying issue.

 

[SharonAcevedo]

I experienced something similar last year, and it turned out that my complaint rate had increased without me realizing it. Once I addressed that, deliverability gradually improved.

 

[azimmerman]

Yahoo pays close attention to recipient engagement. If a large percentage of recipients aren't opening or interacting with your emails, that can impact future delivery.

 

[lgalloway393]

Have you recently changed IPs, domains, or sending patterns? Even relatively small changes can sometimes affect deliverability.

 

[AlexandriaThompson]

One lesson I've learned is that maintaining a clean mailing list is just as important as having good infrastructure. Removing inactive contacts regularly has helped me a lot.

 

[LoriMoore]

If you're consistently sending 200k emails per day, I'd also review your IP reputation. A strong reputation can make a huge difference with Yahoo and AOL.

 

[KerrySoto]

I don't think there's usually a single cause for these types of issues. Deliverability often depends on several factors working together rather than one specific setting.

 

[phernandez]

It might be worth checking whether your authentication records are fully aligned. Even small configuration problems can sometimes affect mailbox provider trust.

 

[Anu Pacheco]

I had a similar experience after increasing my daily volume too quickly. Slowing down and allowing the reputation to recover eventually solved the problem.

 

[AshleyGomez74]

Thanks for posting this. I'm interested in following the discussion because Yahoo deliverability seems to be a common challenge for many email marketers.

 

[wfarrell150]

Have you reviewed your unsubscribe and complaint rates recently? Those metrics can have a significant influence on inbox placement.

 

[ddunn867]

One thing that helped me was segmenting my audience and focusing on my most engaged subscribers first. That improved my overall sender reputation over time.

 

[aallen]

Email deliverability has become much more challenging than it was a few years ago. Mailbox providers now seem to place much greater emphasis on user engagement.

 

[jjimenez201]

I don't have experience with those exact errors, but I'd recommend reviewing every part of your sending setup instead of assuming the issue is with PMTA itself.