Microsoft 365 Outage Update: Outlook Service Issues Continue Tuesday as Recovery Progresses

TL;DR

• Microsoft 365 and Outlook remain partially degraded on Tuesday, September 1, 2026, though Microsoft reports gradual recovery after an outage that began late Monday.
• Outlook on the web, Exchange Online, and Microsoft Teams are the most affected services, with users reporting issues sending emails, loading mailboxes, and accessing calendars.
• Microsoft says it has identified the underlying cause and is rolling out fixes in stages, but has not yet provided a firm timeline for full restoration.

Current Status as of Tuesday Morning

Microsoft 365 is still not fully back to normal on Tuesday, September 1, 2026. According to updates posted to the Microsoft 365 Service health status page and the Microsoft 365 Status account on X, the company is seeing gradual improvements overnight but continues to investigate and mitigate lingering service degradations.

The issues first emerged on Monday afternoon, when users began reporting problems accessing Outlook and other Microsoft 365 services. By Monday evening, Microsoft had acknowledged the incident and said it was investigating an issue impacting mail delivery and mailbox access. As of early Tuesday, the status remains listed as a service degradation rather than a full outage, indicating that functionality is returning for some users while others are still experiencing problems.

Microsoft has not declared the incident resolved and is continuing to provide periodic updates through its admin center and public status channels.

Which Services Are Still Affected

While the scope of the disruption has narrowed since its peak on Monday, several core Microsoft 365 services are still experiencing intermittent issues.

Outlook and Exchange Online remain the most heavily impacted. Users are reporting slow mailbox loading, errors when sending or receiving emails, and temporary failures when searching for messages. Outlook on the web appears to be more affected than desktop and mobile clients, though all versions have seen reports of degraded performance.

Microsoft Teams is also experiencing knock-on effects, particularly with calendar integration, presence status, and meeting scheduling that relies on Exchange Online. Some users have reported delays in Teams chat and issues loading calendar invites.

Other services including SharePoint Online and OneDrive have seen far fewer reports, and Microsoft has indicated that the core issue is centered on Exchange infrastructure. The company says not all users or regions are affected equally, with some tenants already seeing service return to normal while others continue to face errors.

What Microsoft Is Doing to Fix It

In its latest status updates, Microsoft said it has identified the underlying cause of the degradation and is implementing mitigation steps.

The company stated it has isolated a recent service change that triggered performance issues within Exchange Online infrastructure and has begun reverting that change and rebalancing traffic to healthy systems. Microsoft reported that telemetry shows improvement in mail flow and mailbox availability as the fixes propagate through its data centers.

The recovery is being rolled out in stages to avoid further strain on the system. Microsoft said it is closely monitoring the environment, rerouting requests, and restarting affected components where necessary. The company is also working through a backlog of queued emails and calendar updates that built up during the peak of the outage.

Microsoft has not yet shared an estimated time for complete resolution, but said it will continue to post updates until it confirms full recovery and has monitored the services for an extended period of stability.

What Users Can Do in the Meantime

For users still unable to access Outlook or send emails, Microsoft recommends a few temporary workarounds while the fixes continue to deploy.

First, try alternative clients. If Outlook on the web is failing, the desktop Outlook app or the mobile Outlook app may still connect, and vice versa. Restarting the client and clearing browser cache can also help re-establish a connection once your region has been mitigated.

For urgent communications, consider using alternative channels like Microsoft Teams chat, phone, or a secondary email account if available. Admins can check the Microsoft 365 admin center under Service health for tenant-specific status and incident number MO-related updates.

Avoid repeatedly resending the same email if it fails to send, as this can create duplicates once the queue clears. Sent messages that appear stuck in the Outbox or Drafts may still be delivered once the backlog is processed. IT admins are advised to hold off on making major configuration changes until Microsoft confirms the incident is fully resolved.

What's Next

Microsoft says it will continue to monitor service health throughout Tuesday and will declare the incident resolved only after it observes sustained recovery across all affected infrastructure.

Once service is fully restored, the company is expected to publish a Preliminary Post-Incident Report followed by a more detailed root cause analysis within the coming days. Users are encouraged to follow the Microsoft 365 Status page for the latest official updates.

For now, the situation is improving but not over, and users should expect intermittent performance issues to continue for at least the next several hours as the remaining fixes take effect.

AndroGuider Team

Articles written by the AndroGuider team. We try to make them thorough and informational while being easy to read.