Issues delivering to Microsoft

# Email delivery delays involving Microsoft 365 **Status:** Service degradation **Updated:** 4 September 2026, 12:50 CEST We are seeing delays, and in some cases temporary delivery failures, for email sent to or received from mailboxes hosted on Microsoft 365 (Exchange Online). Other mail routes that do not involve Microsoft-hosted mailboxes are operating normally. This is caused by an active Microsoft incident. Microsoft is investigating under issue ID **EX1467029** and currently classifies the issue as a service degradation affecting Exchange Online. ## Impact on our customers - Inbound email to customers whose mailboxes are hosted at Microsoft may be delayed. - Outbound email from our platform to external recipients on Microsoft 365 / Outlook.com may be delayed or temporarily deferred. - Messages are being queued and retried. There is no indication of permanent mail loss at this time. - Some delivery attempts may return intermittent “Server busy” errors from Microsoft. ## Microsoft incident details | Field | Details | |---|---| | Title | Users may experience delays receiving email messages from external domains in Exchange Online | | Issue ID | EX1467029 | | Affected service | Exchange Online | | Issue type | Incident | | Microsoft status | Service degradation | | Start time | 4 September 2026, 12:19 CEST (GMT+2) | | User impact | Delays receiving email messages from external domains in Exchange Online. Intermittent “Server busy” errors may affect multiple mailboxes. | | Scope | Users attempting to receive email from external domains in Exchange Online. Microsoft may update this scope as the investigation continues. | ## Timeline - **4 September 2026, 12:19 CEST** — Microsoft reports the start of incident EX1467029. - **4 September 2026, 12:36 CEST** — Microsoft update: engineers are reviewing service monitoring telemetry to isolate the source of the issue and establish a fix. Next Microsoft update expected by 14:30 CEST. - **4 September 2026, 12:50 CEST** — We confirm impact on mail flow to and from Microsoft-hosted mailboxes. Independent providers are reporting the same symptom. We have notified Microsoft and are monitoring queues and retries. ## What we are doing - Monitoring inbound and outbound queues for Microsoft destinations. - Retrying deferred messages automatically. - Tracking Microsoft incident EX1467029 and related public reports. - Updating this page when Microsoft publishes a new status or when delivery returns to normal. ## What you can do No action is required on your side. Please do not resend large volumes of the same messages, as this can increase queue time. --- Reference: Microsoft 365 Service Health, issue **EX1467029**. Restoration depends on Microsoft completing its remediation for Exchange Online.