Microsoft responds to Microsoft 365 problems affecting email, Teams, and OneDrive

Written on 09/01/2026
On Aug. 31, thousands of users reported Outlook problems. Now, Microsoft says its Exchange Online service has caused widespread problems.a yellow cab moves at a blur in front of microsoft office headquarters

Thousands of Microsoft enterprise customers reported problems accessing their email as they returned from the weekend, and on Monday afternoon, Microsoft acknowledged widespread problems affecting Exchange Online and other Microsoft 365 business services.

Initially, users took to social media and platforms like DownDetector to report problems with Microsoft Outlook, the widely used email service. However, the issue appears to be much more widespread. In a statement shared to X at 12:01 p.m. ET, Microsoft confirmed that service to Exchange Online had been disrupted. (Exchange Online is a cloud-based enterprise service "that delivers email, calendar, contacts, and tasks.")

In addition, a Microsoft spokesperson provided the following statement to Mashable via email: "We're aware of an issue affecting access to Exchange Online and some other services. We know this is disruptive for customers and we appreciate their patience while we work to restore services as quickly as possible."

On its official status page, Microsoft elaborated on what other services were impacted by the outage. The status page reported "Service degradation" for Microsoft 365 Business or Enterprise, with the problems affecting services such as:

  • OneDrive for Business

  • SharePoint Online

  • Exchange Online

  • Microsoft Teams

  • Microsoft Purview

  • Microsoft Defender XDR

  • Microsoft 365 Admin Center

Microsoft says the root cause of the outage is an "issue within a core authentication configuration used by multiple Microsoft 365 services," and the company is actively testing a remediation strategy.

Microsoft 365 admins can see MO1465074 and/or EX1464935 for the latest updates on the disruption — if they can access the Admin Center.

Microsoft provided an update on the situation at 6:01 p.m. ET, writing that it's "continuing to review recent changes to the service to definitively confirm the source of the problem."

Microsoft has since offered further updates, having deployed mitigation measures to help bring its services back online. At 10:01 p.m. ET, the company advised users that its "recovery efforts are ongoing," and that they should see email delivery gradually come back online. Even so, Microsoft warned that its search feature is still experiencing issues.

"We're closely monitoring the health of the service environment amidst our ongoing recovery work, and we're observing some sections of affected infrastructure which aren't accepting the re-applied authentication components as readily as expected," Microsoft wrote on official status page. "Users can expect to see continued recovery to email delivery, while users may see residual impact to downstream and dependent scenarios, including search, across affected services. We're working to identify whether any additional actions are required to expedite full recovery."

At 11:52 p.m. ET, Microsoft reported that mailbox connectivity should now be back to normal, though it was still working on search functionality. The company also noted that it may take a while for backlogged mail queues to clear "due to the volume of previously queued messages."

UPDATE: Sep. 1, 2026, 12:29 p.m. AEST This article has been edited to add updates from Microsoft.

UPDATE: Sep. 1, 2026, 2:02 p.m. AEST This article has been edited to add updates from Microsoft.