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. 

– BG