Yahoo bounces mail in error!

Last week, a small group of ESPs discussed a sudden spike in hard bounces originating from email addresses starting on March 14. Some mentioned seeing an increase as high as 5 times the daily average bounce rate.

This is the error code associated with the spike:

This type of behavior was seen in the past when the mail team at Yahoo (or another domain) purged old or inactive email accounts, so this instance wasn’t immediately seen as an issue… Until individuals at these ESPs started to validate the inactivity of some of these bounced emails. It was found in some cases, the users were active right up until the day before they bounced again, which puts the account clean-up hypothesis right out of play.

Several ESPs escalated the issue to the Postmaster support teams to investigate and comment on, which lead to an investigation into the problem. Yahoo’s team identified and corrected the impacted systems on their network returning a faulty bounce on March 16.

Here at 250ok, we reviewed several client accounts and confirmed this same activity was happening during this time frame. Based on this information, we recommend any Yahoo user identified as a hard bounce during March 14 and March 16 be tried again during the next scheduled mailing.

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