Outage in Microsoft 365
Some users may be intermittently unable to access Outlook on the web
Resolved Minor
June 18, 2026 - Started about 2 months ago
- Lasted about 1 month
Incident Report
Summary AI Generated
A faulty general maintenance deployment caused intermittent Outlook on the web access failures for some users across North America, Europe, and Asia-Pacific on June 18, 2026, from approximately 6:00 PM to 9:25 PM UTC. Exchange Online was the affected component. Microsoft resolved the issue by rolling back the problematic deployment and confirmed remediation through service health telemetry monitoring.
Title: Some users may be intermittently unable to access Outlook on the web
User impact: Users may be intermittently unable to access Outlook on the web.
Current status: We're investigating a potential issue with Exchange Online and checking for impact to your organization. We'll provide an update within 30 minutes.
User impact: Users may be intermittently unable to access Outlook on the web.
Current status: We're investigating a potential issue with Exchange Online and checking for impact to your organization. We'll provide an update within 30 minutes.
Components affected
Exchange OnlineTrusted by 1,000+ teams
The Status Page Aggregator with Early Outage Detection
Stop finding out about outages from your users. Monitor 6,320+ cloud services and get alerted the second something breaks.
Latest Updates ( sorted recent to last )
about 2 months ago - at 06/18/2026 09:57PM
Title: Some users may be intermittently unable to access Outlook on the web
User impact: Users may have been intermittently unable to access Outlook on the web.
Final status: After monitoring service health telemetry, we've confirmed that impact was successfully remediated after completing our rollback of the affecting deployment.
Scope of impact: This issue may have affected some users in North America, Europe and the Asia-Pacific regions.
Start time: Thursday, June 18, 2026, at 6:00 PM UTC
End time: Thursday, June 18, 2026, at 9:25 PM UTC
Root cause: A recent general maintenance deployment caused an issue that resulted in a service availability drop in Outlook on the web.
Next steps:
- We're investigating why this deployment impacted availability to better understand and prevent similar future occurrences.
This is the final update for the event.
about 2 months ago - at 06/18/2026 09:30PM
Title: Some users may be intermittently unable to access Outlook on the web
User impact: Users may be intermittently unable to access Outlook on the web.
Current status: We've identified that a recent general maintenance deployment caused an issue that's resulting in a service availability drop in Outlook on the web, causing intermittent access issues. We've rolled back the impacting deployment and are monitoring as the affected environment recovers to confirm successful impact remediation.
Scope of impact: This issue may affect some users in North America, Europe and the Asia-Pacific regions.
Root cause: A recent general maintenance deployment caused an issue that's resulting in a service availability drop in Outlook on the web.
Next update by: Thursday, June 18, 2026, at 11:30 PM UTC
about 2 months ago - at 06/18/2026 09:09PM
Title: Some users may be intermittently unable to access Outlook on the web
User impact: Users may be intermittently unable to access Outlook on the web.
Current status: We're investigating a potential issue with Exchange Online and checking for impact to your organization. We'll provide an update within 30 minutes.
Latest Microsoft 365 outages
Users may be unable to access Microsoft Copilot Chat in the browser and may encounter a 400 Request Header error - 4 days ago
Some users may be unable to create or publish Microsoft Teams town hall or webinar events that include guest users - 6 days ago
The Status Page Aggregator with Early Outage Detection
With IsDown, you can monitor all your critical services' official status pages from one centralized dashboard and receive instant alerts the moment an outage is detected. Say goodbye to constantly checking multiple sites for updates and stay ahead of outages with IsDown.
Start free trialNo credit card required · Cancel anytime · 6320 services available
Integrations with
