This incident has been resolved.
Apr 26, 13:46 EDT
We are currently delivering to mac.com MX records in all regions. Invalid suppression entries for mac.com, me.com, and icloud.com have been purged from customer suppression lists.
Apr 26, 13:08 EDT
We are continuing to monitor the situation. We are still delaying all mail to mac.com MX records. We will be purging any invalid suppression entries from our system once the incident is complete.
Apr 26, 12:32 EDT
We have delayed all mail to the mac.com MX records.
Apr 26, 09:07 EDT
We are currently seeing high percentage of '550 5.1.1 : user lookup success but no user record found' for valid addresses on the iCloud.com domain. We are currently investigating the issue.
Apr 26, 09:05 EDT