Over the past 10 days or so, many senders have reported an increased number of deferrals for recipients at Yahoo. These deferrals also affect AOL and Verizon addresses, since these are now all running through Yahoo’s mail servers. I’ve seen this firsthand for a few senders, and similar complaints are mounting within various industry channels.
While most of the deferrals seem to be Yahoo’s common “TSS04” error, some senders are reporting other error codes citing limited resources that may or may not be related to this issue. Backing off mail sending (via MTA automation or manual throttles) appears to be having less impact than usual – significant portions of the mail continue to time out and never deliver.
Many senders also report that they are seeing no increase in Yahoo/AOL/VZ complaints to correspond with the surge in deferrals, and some even report a notable complaint decrease. But what changed?
Yahoo’s Postmaster Support has not been able to provide any official response. Some senders report a temporary reprieve after contacting support while others are receiving little to no information from their requests. If you’re experiencing these deferrals, know that you’re not alone. Keep your backoff protocols in place, your Support tickets open, and hold tight until more news drops.
A few weeks ago we told you about AOL’s migration of their MX servers to Yahoo’s infrastructure as part of the merger of the two entities under Verizon’s new Oath brand. Since that change in early February, mail to AOL recipients has been handled by Yahoo’s servers. No specifics have been released on how the combined mail system will handle filtering, but observations of recent bounces may shed some light on that.
Over the past 2-3 weeks a number of senders have been seeing the dreaded “Yahoo deferrals” from recipients with AOL email addresses. These deferrals – temporary bounces usually caused by a high complaint rate – occur frequently for many high-volume senders mailing Yahoo recipients. These bounces are typically returned in a format similar to the following:
421 4.7.0 [XXXX] Messages from XX.XX.XX.XX temporarily deferred due to user complaints – X.X.X.X; see https://help.yahoo.com/kb/postmaster/SLN3434.html
The appearance of these types of bounces when sending to AOL recipients means you now have to contend not only with AOL’s spam filtering but with that of Yahoo. While AOL is known for its useful resources and responsive Postmaster team, the Yahoo Mail team can be more difficult to reach when issues arise. If you do run into any of these bounces, it’s probably a good idea to reach out to Yahoo via their Support form since the filtering is occurring on their mail servers.