SEDNA Outage History

Started Sep 28, 2026, 10:48 AM UTC· resolved Sep 28, 2026, 12:29 PM UTC

1. investigating Sep 28, 2026, 10:48 AM UTC

   An application outage has been identified and is affecting all Sedna customers on the Sedna mobile app. Affected users will be unable to log in to or access the Sedna mobile app. The issue is under investigation by engineering as an emergency.

2. resolved Sep 28, 2026, 12:29 PM UTC

   This incident has been resolved.

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Started Sep 14, 2026, 10:00 AM UTC· resolved Sep 14, 2026, 06:30 PM UTC

1. investigating Sep 14, 2026, 10:48 AM UTC

   Platform performance issues have been identified and are affecting some Sedna customers across clusters. Affected users may experience intermittent slowness when accessing the platform. The issue is under investigation by engineering as an emergency.

2. investigating Sep 14, 2026, 11:16 AM UTC

   We are continuing to investigate this issue.

3. investigating Sep 14, 2026, 12:52 PM UTC

   We are investigating reports of platform performance affecting some customers. We will provide further updates as we learn more.

4. investigating Sep 14, 2026, 02:31 PM UTC

   We are continuing to investigate reports of platform performance affecting some customers. We will provide further updates as we learn more.

5. monitoring Sep 14, 2026, 05:12 PM UTC

   The platform performance issue identified earlier today has been resolved. We're continuing to investigate separate reports of the application becoming unresponsive for a subset of users, and are working directly with affected customers to gather diagnostic information. We'll share further updates as we progress.

6. resolved Sep 15, 2026, 07:28 AM UTC

   This incident has been resolved.

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Started Sep 04, 2026, 09:36 AM UTC· resolved Sep 04, 2026, 08:09 PM UTC

1. investigating Sep 04, 2026, 09:36 AM UTC

   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.

2. identified Sep 04, 2026, 10:50 AM UTC

   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.

3. identified Sep 04, 2026, 01:44 PM UTC

   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.

4. monitoring Sep 04, 2026, 02:58 PM UTC

   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.

5. monitoring Sep 04, 2026, 03:39 PM UTC

   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

6. monitoring Sep 04, 2026, 06:02 PM UTC

   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

7. resolved Sep 04, 2026, 08:09 PM UTC

   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.

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Started Aug 31, 2026, 07:49 PM UTC· resolved Sep 04, 2026, 08:45 AM UTC

1. investigating Aug 31, 2026, 07:49 PM UTC

   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.

2. investigating Aug 31, 2026, 07:49 PM UTC

   We are continuing to investigate this issue.

3. investigating Sep 01, 2026, 01:28 AM UTC

   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.

4. investigating Sep 01, 2026, 07:46 AM UTC

   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.

5. investigating Sep 02, 2026, 02:30 AM UTC

   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.

6. investigating Sep 02, 2026, 09:28 AM UTC

   We are continuing to investigate this issue.

7. monitoring Sep 02, 2026, 09:29 AM UTC

   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.

8. resolved Sep 04, 2026, 08:45 AM UTC

   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.

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Started Aug 18, 2026, 05:20 PM UTC· resolved Aug 18, 2026, 06:27 PM UTC

1. investigating Aug 18, 2026, 05:28 PM UTC

   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.

2. identified Aug 18, 2026, 06:09 PM UTC

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

3. resolved Aug 18, 2026, 06:27 PM UTC

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

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Started Aug 17, 2026, 06:40 PM UTC· resolved Aug 17, 2026, 07:38 PM UTC

1. investigating Aug 17, 2026, 06:48 PM UTC

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

2. identified Aug 17, 2026, 07:17 PM UTC

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

3. monitoring Aug 17, 2026, 07:36 PM UTC

   All queued messages have been redriven.

4. resolved Aug 17, 2026, 07:43 PM UTC

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

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Started Aug 13, 2026, 11:00 PM UTC· resolved Aug 16, 2026, 09:00 AM UTC

1. investigating Aug 15, 2026, 11:15 AM UTC

   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.

2. monitoring Aug 15, 2026, 11:26 AM UTC

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

3. investigating Aug 15, 2026, 11:30 AM UTC

   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.

4. monitoring Aug 16, 2026, 08:15 AM UTC

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

5. investigating Aug 16, 2026, 08:16 AM UTC

   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.

6. monitoring Aug 16, 2026, 11:10 AM UTC

   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.

7. resolved Aug 16, 2026, 11:12 AM UTC

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

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Started Jul 23, 2026, 11:30 AM UTC· resolved Jul 23, 2026, 12:50 PM UTC

1. resolved Jul 23, 2026, 12:59 PM UTC

   An issue affecting Sedna’s mail ingress services in the Dublin 2 cluster has been resolved. During the incident, affected users were unable to receive incoming emails. Our engineering team identified and fixed the root cause, and mail flow has fully stabilized.

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Started Jul 19, 2026, 11:22 AM UTC· resolved Jul 19, 2026, 12:08 PM UTC

1. identified Jul 19, 2026, 11:22 AM UTC

   An outage affecting Sedna’s mail egress and ingress services has been identified on a specific infrastructure cluster (eu-west-1). Affected users are unable to send and receive mail. The issue is under investigation by engineering as an emergency.

2. resolved Jul 19, 2026, 12:08 PM UTC

   Earlier today, some customers hosted on our European clusters experienced delays to email processing due to an infrastructure issue. This has been resolved, and all queued mail from this incident has now been processed.

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Started Jul 15, 2026, 12:10 PM UTC· resolved Jul 15, 2026, 12:14 PM UTC

1. investigating Jul 15, 2026, 12:10 PM UTC

   Sedna has been upgrading our general authentication posture, with non-urgent planned maintenance work scheduled for an upcoming weekend to complete it, work that would not normally affect users. This morning we became aware of a potential compromise of infrastructure at an integration partner and out of an abundance of caution we accelerated the upgrade, pushing it across the network immediately. This disrupted authentication for around an hour. We have found no evidence of any unauthorised access to Sedna data or systems. Our review of logs and API activity is continuing, and the change itself is a modernisation of how we interact with Auth0.com, our authentication provider. All users should now be able to log in normally; if you have any trouble, log out fully and back in, or contact support. We take this seriously and will share more once our investigation is complete.

2. resolved Jul 15, 2026, 12:14 PM UTC

   This incident has been resolved.

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Started Jun 03, 2026, 03:47 PM UTC· resolved Jun 04, 2026, 01:13 PM UTC

1. investigating Jun 03, 2026, 03:47 PM UTC

   An application outage has been identified and is affecting some Sedna customers across infrastructure clusters. Affected users are unable to log into or access the platform. The issue is under investigation by engineering as an emergency.

2. investigating Jun 04, 2026, 08:54 AM UTC

   We are currently investigating reports of degraded performance affecting some users on the Sedna platform. Affected users may experience slowness when navigating Sedna. Users are still able to log in and access the platform. Our engineering team is actively investigating the root cause as a priority. We will provide further updates as our investigation progresses. We apologise for any inconvenience caused.

3. resolved Jun 04, 2026, 01:13 PM UTC

   This incident has been resolved.

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Started Jun 03, 2026, 03:05 PM UTC· resolved Jun 04, 2026, 03:10 PM UTC

1. investigating Jun 04, 2026, 01:22 PM UTC

   Platform performance issues have been identified and are affecting some Sedna customers across different clusters. Affected users may experience slowness when accessing the platform. The issue is under investigation by engineering as an emergency.

2. identified Jun 04, 2026, 01:24 PM UTC

   We have identified the root cause of the issue and have implemented a fix.

3. monitoring Jun 04, 2026, 01:25 PM UTC

   We are currently investigating reports of degraded performance affecting some users on the Sedna platform. Affected users may experience slowness when navigating Sedna. Users are still able to log in and access the platform. Our engineering team is actively investigating the root cause as a priority. We will provide further updates as our investigation progresses. We apologise for any inconvenience caused.

4. identified Jun 04, 2026, 01:29 PM UTC

   The issue has been identified and a fix is currently being implemented. Sedna's Engineering team will continue to monitor the situation closely

5. monitoring Jun 04, 2026, 01:31 PM UTC

   A fix has been implemented and we are monitoring the results.

6. resolved Jun 05, 2026, 09:57 AM UTC

   This incident has been resolved.

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Started Apr 28, 2026, 10:30 AM UTC· resolved Apr 28, 2026, 06:09 PM UTC

1. investigating Apr 28, 2026, 10:30 AM UTC

   An application outage was identified affecting some Sedna customers on our Dublin 1 and Dublin 2 clusters between 7:30am and 08:00 am UTC and 9:20am and 09:35 and UTC. During this time, impacted users were unable to log in or access the platform. The issue is being treated as an emergency by our engineering team while service is being restored. We are continuing to monitor the platform closely to ensure stability and will keep you updated as the investigation progresses.

2. monitoring Apr 28, 2026, 01:53 PM UTC

   .

3. resolved Apr 28, 2026, 06:09 PM UTC

   An initial investigation has been completed into the outage that affected some Sedna customers on our Dublin 1 and Dublin 2 clusters earlier today. The disruption was traced to a capacity issue that prevented impacted users from logging in or accessing the platform. As a precautionary measure, we have adjusted scaling policies on both clusters and temporarily disabled a non-essential feature to reduce load. Our engineering team is continuing the root cause analysis and will implement further improvements to prevent recurrence.

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Started Apr 27, 2026, 07:50 AM UTC· resolved Apr 27, 2026, 07:50 AM UTC

1. resolved Apr 27, 2026, 08:29 AM UTC

   An application outage was identified affecting some Sedna customers on our Dublin 2 cluster. During this time, impacted users were unable to log in or access the platform. The issue was treated as an emergency by our engineering team and has now been resolved. A root cause analysis is currently underway, and Sedna’s engineering team is actively investigating to determine the underlying cause and prevent recurrence.

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Started Apr 20, 2026, 10:10 AM UTC· resolved Apr 20, 2026, 10:40 AM UTC

1. resolved Apr 20, 2026, 12:06 PM UTC

   This morning (between approximately 10:10 and 10:40 UTC), we experienced a performance degradation of email ingress and egress in our Dublin2 and Dublin3 clusters. This issue was brought to our attention by automated alerting built on our internal observability tooling. Application scaling policies increased capacity during this period, reducing its overall length. This was a repeated issue, seen previously on 16th March, caused by abnormally expensive processing of a set of malformed emails sent to a large number of recipients. Mitigation steps we have taken so far have unfortunately not been sufficient to avoid a recurrence, and as such, we will continue to investigate to improve resilience.

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Started Mar 23, 2026, 10:45 AM UTC· resolved Mar 23, 2026, 10:45 AM UTC

1. resolved Mar 23, 2026, 10:45 AM UTC

   The issue causing elevated CPU load in the Dublin2 cluster has been identified and mitigated. We have implemented measures to prevent recurrence. All services have resumed and should now be operating normally.

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Started Mar 18, 2026, 10:48 AM UTC· resolved Mar 18, 2026, 01:09 PM UTC

1. investigating Mar 18, 2026, 10:48 AM UTC

   We are investigating reports of delayed mail between 10:20 am and 10:35 am GMT. We have implemented a corrective measure and are seeing normal mail delivery. Our engineering team is actively investigating the cause. We will provide further updates as soon as more information becomes available.

2. resolved Mar 18, 2026, 01:09 PM UTC

   Correct measures was put in place once delay was noted by our engineers. This has been monitored and we can confirm that service has been restored and is working as expected.

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Started Mar 16, 2026, 12:37 PM UTC· resolved Mar 16, 2026, 01:16 PM UTC

1. investigating Mar 16, 2026, 12:37 PM UTC

   We are currently investigating an issue affecting mail ingress and egress globally. From 11:30 to 12:00 UTC some customers may have experienced delays or disruptions in email processing. Our engineering team is actively investigating the cause. We will provide further updates as soon as more information becomes available.

2. monitoring Mar 16, 2026, 12:41 PM UTC

   System appears to be operational. Our engineering team will continue to monitor this from our end.

3. resolved Mar 16, 2026, 01:16 PM UTC

   Earlier today (from 11:31 to 12:09 UTC) we experienced a performance degradation of email ingress and egress globally across tenants in our public clusters. This was caused by abnormally expensive processing of a set of malformed emails sent to a large number of recipients. We will continue to monitor and investigate how our systems can be updated to improve resilience.

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Started Feb 12, 2026, 06:48 PM UTC· resolved Feb 12, 2026, 08:38 PM UTC

1. investigating Feb 12, 2026, 06:48 PM UTC

   An outage affecting Sedna’s mail egress and ingress services has been identified on specific infrastructure EU clusters. Affected users are unable to send and receive mail. The issue is under investigation by engineering as an emergency.

2. investigating Feb 12, 2026, 07:51 PM UTC

   We are continuing to investigate this issue, and will update every hour until it is resolved.

3. monitoring Feb 12, 2026, 08:18 PM UTC

   Clusters are now healthy, and the backlog is being processed, we estimate 30 minutes.

4. resolved Feb 12, 2026, 08:38 PM UTC

   This incident has been resolved, and all back logged messages have been processed

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Started Jan 22, 2026, 09:00 PM UTC· resolved Jan 23, 2026, 07:01 AM UTC

1. investigating Jan 23, 2026, 04:36 AM UTC

   Microsoft Outage: Degraded Service Microsoft is currently experiencing degraded service functionality. As a result, recipients using Microsoft mailboxes may not receive emails, and messages sent from Sedna may result in NDRs. Updates on Microsoft’s Service Health Status can be found here: https://status.cloud.microsoft/m365

2. investigating Jan 23, 2026, 04:37 AM UTC

   We are continuing to investigate this issue.

3. resolved Jan 23, 2026, 07:01 AM UTC

   This incident has been resolved.

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Started Jan 15, 2026, 10:45 PM UTC· resolved Jan 16, 2026, 12:15 AM UTC

1. investigating Jan 16, 2026, 03:16 AM UTC

   An outage affecting Sedna’s mail egress and egress services has been identified across our Virginia1 Cluster. Affected users may experience delays with sending and receiving mail. The issue is under investigation by Sedna's Engineering team as an emergency.

2. resolved Jan 16, 2026, 03:19 AM UTC

   This incident has been resolved.

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Started Jan 15, 2026, 08:55 PM UTC· resolved Jan 15, 2026, 09:30 PM UTC

1. investigating Jan 15, 2026, 08:55 PM UTC

   We are currently investigating this issue.

2. investigating Jan 15, 2026, 08:56 PM UTC

   An outage affecting Sedna’s mail egress and ingress services has been identified on specific infrastructure EU clusters. Affected users are unable to send and receive mail. The issue is under investigation by engineering as an emergency.

3. resolved Jan 15, 2026, 09:30 PM UTC

   This incident has been resolved.

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Started Dec 10, 2025, 09:39 AM UTC· resolved Dec 10, 2025, 09:47 AM UTC

1. monitoring Dec 10, 2025, 09:39 AM UTC

   Estimated impact window: 08:40–09:05 UTC During this time, mail could not be sent or received in our EU cluster. Service has since fully recovered, and the system is currently healthy. All incoming mail from the affected window has been successfully reprocessed and no messages were lost. Any outbound messages that could not be delivered would have generated an NDR; if you received one, please resend the message. We are investigating the root cause and will provide further updates. In the interim, if you notice any mail delivery failures or unexpected behaviour, please let us know.

2. resolved Dec 10, 2025, 09:47 AM UTC

   This incident has been resolved.

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Started Oct 27, 2025, 10:38 AM UTC· resolved Oct 27, 2025, 10:41 AM UTC

1. identified Oct 27, 2025, 10:38 AM UTC

   Dear Customers, We’re aware that some may currently be experiencing issues creating and receiving new mail. Our engineering team is actively investigating and working to resolve the issue as quickly as possible. We’ll provide updates as the engineering team progress on resolving the issue. Next update estimated in 15 mins

2. resolved Oct 27, 2025, 10:41 AM UTC

   Dear Customers, Mail delivery services have now been restored, and new mail is flowing as expected. Thank you for your patience

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Started Oct 20, 2025, 04:44 PM UTC· resolved Oct 20, 2025, 09:00 PM UTC

1. monitoring Oct 20, 2025, 04:44 PM UTC

   Platform performance issues have been identified and are affecting some Sedna customers across infrastructure clusters (virginia1 and default). Affected users may see slowness and/or spinners intermittently when accessing the platform, specifically impacting auto-tagging functionality. The issue is under investigation by engineering as an emergency and is related to the AWS incident from earlier today.

2. resolved Oct 21, 2025, 07:09 AM UTC

   Dear Customer, We're pleased to inform you that the latest update from AWS is that the issue has now been completely resolved. https://health.aws.amazon.com/health/status All systems are working as expected and all services should be back to full operational efficiency. Thank you for your patience and understanding

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