Delivery delays for messages sent from Outlook and Exchange

Summary

Delivery delays for messages sent from Outlook and Exchange

Mail delivery has resumed as normal and our engineers are seeing significantly less errors. The team are awaiting confirmation of a fix implemented on Microsoft servers and will be monitoring until tomorrow morning to confirm.

• Started

  Sep 22, 2026 · 10:58 AM

• Status

  Monitoring

• Duration

  Ongoing

• Severity

  None

• ◐

  Investigating

  Sep 22 · 10:58 AM Exclaimer

  Exclaimer engineers are investigating a delivery delay affecting some messages sent from Outlook and Exchange to Exclaimer Cloud. Some of these messages may be retried by the sender and may appear as temporary deferrals rather than delivery failures. We are not currently aware of any confirmed message loss and will provide updates as we learn more.

• ◆

  Identified

  Sep 22 · 3:19 PM Exclaimer

  Exclaimer has identified that a small subset of messages (~0.02%) are delayed when routed through Exclaimer due to a suspected issue within Microsoft's servers. This has been raised with Microsoft to investigate alongside Exclaimer Engineers. Sent messages will be received with a signature applied, as expected. If you are seeing issues with message deliverability, please reach out to our support team, who will be happy to assist.

• ◉

  Monitoring

  Sep 27 · 7:33 PM Exclaimer

  Mail delivery has resumed as normal and our engineers are seeing significantly less errors. The team are awaiting confirmation of a fix implemented on Microsoft servers and will be monitoring until tomorrow morning to confirm.