Exclaimer engineers have continued to monitor the Microsoft incidents (MO1550821 and EX1550543) overnight for any signs of improvement in Microsoft's own mitigation actions. At this time the incident looks to be ongoing and we are continuing to monitor for any action we can take and to reduce further delays once the impact to Exchange Online has been resolved.
Currently, impacted emails are delayed, they will be automatically retried for delivery. This means no action is needed from you at this time; once we have the email, we will be able to apply a signature as expected.
Posted Nov 13, 2026 - 00:39 UTC
Update
We are continuing to monitor the impact of this issue as Microsoft works to mitigate it.
Posted Nov 12, 2026 - 18:52 UTC
Investigating
We’re seeing delays delivering emails to Microsoft 365 (Outlook) recipients across all regions, due to an issue on Microsoft’s side affecting their mail infrastructure. Emails are delayed and being automatically retried, not lost. No action is needed from you. We’re monitoring and will post updates as we learn more.
Posted Nov 12, 2026 - 18:51 UTC
This incident affects: Europe (EU: Server-Side: Mail Routing - Office 365), US (US: Server-Side: Mail Routing - Office 365), Canada (CA: Server-Side: Mail Routing - Office 365), UAE (UAE: Server-Side: Mail Routing - Office 365), Australia (AU: Server-Side: Mail Routing - Office 365), UK (UK: Server-Side: Mail Routing - Office 365), and Germany (DE: Server-Side: Mail Routing - Office 365).