Some users may be intermittently unable to send email messages to Outlook.com, Hotmail.com, or Live.com email addresses

Timeline (UK time)

1. 10 Nov 2026, 05:36 GMT ✓ Operational

   Title: Some users may be intermittently unable to send email messages to Outlook.com, Hotmail.com, or Live.com email addresses User impact: Users may have been unable to send email messages to Outlook.com, Hotmail.com, or Live.com email addresses. More info: Users may have received a Non-Delivery Report (NDR) reporting 550 5.7.1 or 550 5.7.23 due to Service Provider Foundation (SPF) violation. Final status: We've investigated the provided logs and our service health telemetry, and identified a recent update to the spam enforcement rules caused email messages to be incorrectly marked and blocked, which led to impact. We've fully rolled back this update and confirmed that mail flow has been restored and impact is resolved. Scope of impact: Some users may have intermittently been unable to send email messages to Outlook, Hotmail, and Live email accounts. Start time: Friday, November 6, 2026, at 6:00 PM UTC End time: Monday, November 9, 2026, at 11:02 AM UTC Root cause: A recent update to the spam enforcement rules caused email messages to be incorrectly marked and blocked, which led to impact. Next steps: - We're reviewing our update procedures and improving our mail detection logic to lower the false positive rate and ensure that legitimate email messages aren’t inaccurately blocked. This is the final update for the event.

2. 9 Nov 2026, 05:24 GMT ✓ Operational

   Title: Some users may be intermittently unable to send email messages to Outlook.com, Hotmail.com, or Live.com email addresses User impact: Users may be intermittently unable to send email messages to Outlook.com, Hotmail.com, or Live.com email addresses. More info: Users may receive a Non-Delivery Report (NDR) reporting 550 5.7.1 or 550 5.7.23 due to Service Provider Foundation (SPF) violation. Current status: We've received reports indicating that some users may be unable to send email messages to Outlook.com, Hotmail.com or Live.com email addresses. We're requesting that affected users reach out to their support representatives and provide fresh Network Message IDs, fresh logs, and examples of impact users are facing in .eml format. These logs will aid in the root cause investigation into why impact persists, so we can identify a remediation plan. Scope of impact: Some users may be intermittently unable to send email messages to Outlook, Hotmail, and Live email accounts. Next update by: Wednesday, November 11, 2026, at 7:00 AM UTC