Is SEDNA down?

An outage affecting Sedna’s mail egress services has been identified. Affected users are unable to send mail. The issue is under investigation by engineering as an emergency.

We are investigating an issue affecting outbound email from Sedna to recipients hosted on Microsoft 365 and Outlook. Microsoft's anti-spam filtering is rejecting messages sent from a number of our outbound IP addresses, and senders are receiving bounce-back notifications (NDRs) for affected messages. Inbound mail is not affected, and delivery to recipients outside of Microsoft 365 / Outlook is unaffected.

We are continuing to investigate an issue affecting outbound email from Sedna to recipients hosted on Microsoft 365 and Outlook. What's happening: Microsoft's anti-spam filtering is rejecting messages sent from a number of our outbound IP addresses. Senders are receiving bounce-back notifications (NDRs) for affected messages. We will post updates as the investigation progresses.

We are seeing signs of recovery in mail delivery to Microsoft 365 and Outlook recipients, and are continuing to monitor closely to confirm the issue is fully resolved. Microsoft has acknowledged the issue on their end, and updates from Microsoft can be tracked at: https://x.com/MSFT365Status. We will post a further update once we've confirmed full recovery.

We are continuing to see a recovery in our services for customers sending to Microsoft and MS 365 supported recipients, and we'll continue to monitor. We'll provide more updates as soon as they become available

We are continuing to see a recovery in our services for customers sending to Microsoft and MS 365 supported recipients, and we'll continue to monitor. We'll provide more updates as soon as they become available

This incident has been resolved. Mail delivery to Microsoft 365 and Outlook recipients has returned to normal. We saw no further reports of delayed or failed delivery following confirmation from affected customers and our monitoring.

Microsoft has reported service degradation that may affect outbound emails sent from Sedna via Microsoft Graph. Customers may experience delays or failures when sending emails. We are monitoring the situation and will provide updates as they become available.

We are continuing to investigate this issue.

The Microsoft service degradation is still ongoing. Microsoft has not yet provided an estimated time for resolution. We continue to monitor the situation and will provide further updates as they become available.

Some users are reporting improved mail flow this morning. Microsoft's service degradation (EX1464935) remains listed as active as of 06:39 UTC, and we continue to monitor closely. We will post a further update once Microsoft confirms full resolution or if conditions change.

We have received reports that services have returned to normal. Microsoft’s service degradation, EX1464935, remains listed as active as of September 2, 2026, at 01:32:37 UTC. We will continue to monitor the situation closely and provide a further update once Microsoft confirms full resolution or if conditions change.

We are continuing to investigate this issue.

Microsoft has reported that core mail flow and search functionality are recovering, with service availability above 99%. The majority of users should no longer be experiencing impact. We are continuing to monitor to confirm persistent stability before closing this incident. Microsoft's next update is expected by September 2, 2026, at 4:30 PM UTC. We will update this page accordingly.

Resolved – Microsoft has confirmed full recovery from the service degradation affecting Graph-based mail flow (EX1464935). All Sedna services related to Microsoft Graph email egress are now operating normally. We've seen no further reports of impact since our last update. Thank you for your patience while we monitored this alongside Microsoft.

An outage affecting Sedna’s mail egress services has been identified on our Virginia 1 clusters. Affected users are unable to send mail. The issue is under investigation by engineering as an emergency.

The issue has been identified and a fix is being implemented.

This incident has been resolved. Any messages that bounced during the incident can continue to be resent.

Our team is monitoring alarms on tenants hosted in Europe. We will provide updates as we know more about any potential impact

The issue has been identified and a fix is being implemented.

All queued messages have been redriven.

Any mail delayed during the outage has now been processed, and mail flow is operating normally.

We are investigating an issue affecting outbound email from Sedna to recipients hosted on Microsoft 365 and Outlook. Microsoft's anti-spam filtering is rejecting messages sent from a number of our outbound IP addresses, and senders are receiving bounce-back notifications (NDRs) for affected messages. Inbound mail is not affected, and delivery to recipients outside of Microsoft 365 / Outlook is unaffected. We will provide further updates as our investigation progresses.

We are monitoring closely and continuing to work with Microsoft. Any messages that bounced during the incident can now be resent.

We are seeing further reports of outbound emails to Microsoft 365 and Outlook recipients being rejected. The issue is ongoing and our engineering team is continuing to work with Microsoft and our email delivery provider on a resolution. Inbound mail remains unaffected. Bounced messages were not lost and can be resent once delivery is restored.

We are monitoring closely and continuing to work with Microsoft. Any messages that bounced during the incident can now be resent.

We are seeing further reports of outbound emails to Microsoft 365 and Outlook recipients being rejected. The issue is ongoing and our engineering team is continuing to work with Microsoft and our email delivery provider on a resolution. Inbound mail remains unaffected. Bounced messages were not lost and can be resent once delivery is restored.

Some customers are experiencing SPF bounces, this is a side effect of the mitigation and not a continuation of the issue. We are continuing to monitor closely before confirming full resolution. Any messages that bounced during the incident can continue to be resent.

This incident has been resolved. Any messages that bounced during the incident can continue to be resent.