Summary: Beginning last week we made a change to add a URL to the list-unsubscribe header to be compliant with new rule “one-click” unsubscribe requirements from Gmail and Yahoo. After this update, some customers started reporting an increase in [new] junk foldering of messages destined to Office 365 addresses - it appears they were flagged by Microsoft’s Defender filtering framework. We worked with Microsoft who made changes to address this issue. In addition, some customers reported a large increase in opens and clicks on Monday and Tuesday of this week that we believe were caused by some action by Microsoft - likely a reclassification or redelivery routine.
Posted Feb 07, 2024 - 17:03 EST
Update
Customers are reporting improvements and we continue to work with Microsoft on this issue. We will continue to monitor and we'll provide another update by 5 PM EST today.
Posted Feb 07, 2024 - 10:58 EST
Update
We continue to communicate with Microsoft on this issue; they are responsive and are working on changes on their side; some customers are reporting improvements. We will continue to monitor and we'll provide another update by noon EST on Wednesday.
Posted Feb 06, 2024 - 18:42 EST
Monitoring
Microsoft have communicated to us that they have made updates to address these issues; customers are no longer reporting an uptick in opens.
Posted Feb 06, 2024 - 14:56 EST
Identified
Last week we rolled out a change to support the new list-unsubscribe header requirements for Gmail and Yahoo; this caused Microsoft to quarantine some messages for Office365 addresses; we are working with Microsoft on this issue. Some recipients are reporting receiving multiple copies of messages.
Posted Feb 06, 2024 - 12:56 EST
This incident affected: SMTP Delivery (Outbound Message Delivery) (SMTP Delivery - USA, SMTP Delivery - EUROPE).