Outage in Microsoft 365
Some users may be unable to send or receive new Exchange Online email through the native iOS mail app
Resolved Minor
August 17, 2026 - Started about 10 hours ago
- Lasted about 4 hours
Incident Report
Summary AI Generated
Some users were unable to send or receive Exchange Online email through the native iOS mail app for approximately 4 hours starting August 17, 2026. The root cause was a recent change to an authentication component used by Exchange ActiveSync, which caused connection failures. Microsoft identified the problematic change and initiated a rollback to restore service.
Title: Some users may be unable to send or receive new Exchange Online email through the native iOS mail app
User impact: Users may be unable to send or receive new Exchange Online email through the native iOS mail app.
Current status: We're reviewing service logs, telemetry, and contextual details provided by impacted users to gain insight into the underlying source of impact and determine our next steps.
Scope of impact: Some users attempting to send or receive new Exchange Online email through the native iOS mail app may be impacted. This information may be updated as our investigation continues.
Next update by: Tuesday, August 18, 2026, at 5:00 AM UTC
User impact: Users may be unable to send or receive new Exchange Online email through the native iOS mail app.
Current status: We're reviewing service logs, telemetry, and contextual details provided by impacted users to gain insight into the underlying source of impact and determine our next steps.
Scope of impact: Some users attempting to send or receive new Exchange Online email through the native iOS mail app may be impacted. This information may be updated as our investigation continues.
Next update by: Tuesday, August 18, 2026, at 5:00 AM UTC
Components affected
Exchange OnlineTrusted by 1,000+ teams
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Latest Updates ( sorted recent to last )
about 6 hours ago - at 08/18/2026 06:48AM
Title: Some users may be unable to send or receive new Exchange Online email through the native iOS mail app
User impact: Users may be unable to send or receive new Exchange Online email through the native iOS mail app.
Current status: After reviewing the logs, we identified that there were recent changes to an authentication component utilized for Exchange ActiveSync that is causing connection failures. We're working to revert the problematic changes, which we anticipate should remediate the impact by the time of our next scheduled update, at which point we'll reach out to confirm with a subset of impacted users.
Scope of impact: Some users attempting to send or receive new Exchange Online email through the native iOS mail app are impacted.
Start time: Monday, August 17, 2026, at 11:38 PM UTC
Root cause: Recent changes to an authentication component utilized for Exchange ActiveSync are causing connection failures.
Next update by: Tuesday, August 18, 2026, at 9:00 AM UTC
about 8 hours ago - at 08/18/2026 05:06AM
Title: Some users may be unable to send or receive new Exchange Online email through the native iOS mail app
User impact: Users may be unable to send or receive new Exchange Online email through the native iOS mail app.
Current status: We're continuing our analysis of service-side logs and Exchange ActiveSync logs collected from impacted users to understand the source of the issue and determine our next troubleshooting steps.
Scope of impact: Some users attempting to send or receive new Exchange Online email through the native iOS mail app may be impacted. This information may be updated as our investigation continues.
Next update by: Tuesday, August 18, 2026, at 7:00 AM UTC
about 10 hours ago - at 08/18/2026 03:27AM
Title: Some users may be unable to send or receive new Exchange Online email through the native iOS mail app
User impact: Users may be unable to send or receive new Exchange Online email through the native iOS mail app.
Current status: We're reviewing service logs, telemetry, and contextual details provided by impacted users to gain insight into the underlying source of impact and determine our next steps.
Scope of impact: Some users attempting to send or receive new Exchange Online email through the native iOS mail app may be impacted. This information may be updated as our investigation continues.
Next update by: Tuesday, August 18, 2026, at 5:00 AM UTC
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