Reprinted from TidBITS by permission; reuse governed by Creative Commons
license BY-NC-ND 3.0. TidBITS has offered years of thoughtful commentary
on Apple and Internet topics. For free email subscriptions and access to the
entire TidBITS archive, visit http://www.tidbits.com/


                  Resetting Recent iCloud Bouncing Subscribers

   Adam Engst

   Three weeks ago, starting with TidBITS #1574, Apple's iCloud Mail
   servers decided that there was something about the TidBITS issues they
   didn't like and started rejecting issues with this error:

     SMTP Errors: 554 5.7.1 [CS01] Message rejected due to local policy.
     Please visit https://support.apple.com/en-us/HT204137

   It took our support expert Lauri Reinhardt a little while to piece
   together questions from subscribers and her own tests. Once she had
   assembled a coherent picture of what was going on, I reported the
   problem to iCloud Mail support. Two days later, the iCloud Mail team
   told me that they had made appropriate changes to resolve the delivery
   problems. My tests confirmed that, but there was more to do.

   The problem was that [1]Sendy, our mailing list management software,
   had marked over 300 iCloud users as bouncing. (That may seem like a
   lot, but we have well over 5000 iCloud subscribers all told. I can't
   explain why such a small percentage bounced.) I have reset all those
   addresses, so in theory, everyone who failed to get the last issue or
   three should receive TidBITS #1577 on 30 August 2021.

   I say 'in theory' because there's another variable. Sendy gives us an
   interface for funneling messages to the [2]Amazon Simple Email Service
   for the actual delivery. Amazon SES maintains a global suppression list
   that prevents email from going out to an address that has recorded a
   hard bounce for any Amazon SES user. We can remove addresses from
   Amazon SES's global suppression list when we know they're good and have
   fixed whatever problem was causing the bounces. But we have to do that
   one address at a time, with a CAPTCHA, and there's no way to query the
   list or even know if a removed address was on the list'all that Amazon
   SES tells us is that the address was removed if it was on the list.
   Doing that one by one with over 300 addresses would be a royal pain.

   The Amazon SES user guide says that [3]Amazon SES automatically removes
   addresses from the global suppression list, increasing the amount of
   time an address stays on the list after each bounce. The longest an
   address will remain on the list is 14 days, and since TidBITS
   subscribers wouldn't have bounced more than three times, I'm hoping
   Amazon SES has already removed all those addresses. If not, it should
   happen before TidBITS#1578 comes out on 6 September 2021.

   With any luck, then, this situation will go away either this week or
   next. Our apologies for any confusion it may have caused'it's yet
   another example of how systemic anti-social behavior by some (spammers)
   causes ongoing headaches for the rest of us.

References

   Visible links
   1. https://sendy.co/
   2. https://aws.amazon.com/ses/
   3. https://docs.aws.amazon.com/ses/latest/DeveloperGuide/sending-email-global-suppression-list.html

   Hidden links:
   4. https://tidbits.com/wp/../uploads/2021/08/Amazon-SES-black-box.png

.