If Microsoft Outlook refused to load, emails were delayed, search stopped working or your Microsoft 365 account suddenly acted strangely on Monday, August 31, you weren’t alone.
Microsoft experienced a significant Microsoft 365 service disruption that hit Exchange Online particularly hard, affecting email and other functions used by businesses and organizations around the world. The incident began Monday and continued into Tuesday, September 1, as Microsoft gradually restored affected infrastructure.
The good news is that the situation has improved considerably.
As of the latest check on September 1, 2026, Microsoft’s public Service Health Status page says that all products are operational. That means Microsoft is no longer showing an active broad service degradation on its public status dashboard.
So if you’re asking the question many people have been searching:
“Is Outlook still down?”
The answer right now is: Microsoft’s public status page says its services are operational.
But that doesn’t mean the outage wasn’t serious. For many users, the disruption lasted for hours, affected more than just email, and required Microsoft to restart portions of its infrastructure as part of the recovery.
Here’s what happened, what Microsoft says caused it, which services were affected, and what you can do if Outlook still isn’t working for you.
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Outlook Outage 2026: Quick Update
Here are the most important details.
| Question | Latest information |
|---|---|
| Is Outlook down right now? | Microsoft’s public status page currently shows all products operational |
| When did the outage begin? | Monday, August 31, 2026 |
| Main service affected | Exchange Online / Microsoft 365 |
| What did users experience? | Email delays, sending and receiving failures, login/authentication problems, search issues and other degraded functions |
| Confirmed cause | An issue involving a core authentication configuration used by multiple Microsoft 365 services |
| Was Outlook the only service affected? | No |
| Other affected Microsoft services | Included SharePoint, OneDrive, Teams-related functions, Microsoft 365 Copilot, Purview, Defender XDR, Microsoft 365 Admin Center and Universal Print |
| Current Microsoft public status | All products operational |
Microsoft’s incident information attributed the disruption to an issue involving a core authentication configuration shared by multiple Microsoft 365 services.
Is Microsoft Outlook Down Right Now?
According to Microsoft’s current public service-health dashboard, no broad Microsoft outage is being reported at the moment.
Microsoft’s status page currently displays:
“All products are operational.”
That includes the company’s public Microsoft 365 status overview as well as its consumer-products status section.
This is an important change from earlier Tuesday.
During the morning of September 1, Microsoft was still describing its mitigation work as ongoing. The company said its telemetry was showing positive signs and service availability was improving, but it had not yet declared everything fully restored. Microsoft then entered an extended monitoring period while checking whether its fixes had worked throughout the affected infrastructure.
The latest public status now indicates normal operation.
That said, an official status of “operational” doesn’t guarantee that every individual Outlook problem has disappeared.
If Outlook still isn’t working for you, your issue could be related to:
- delayed synchronization following the outage
- a local Outlook app problem
- cached credentials
- an internet connection issue
- an organizational Microsoft 365 configuration
- an isolated regional or account issue
- a separate Microsoft incident not yet reflected in broad outage reports
So it’s worth doing a little troubleshooting before assuming the widespread outage has returned.
What Happened to Microsoft Outlook?
The outage began Monday, August 31, and was primarily associated with Microsoft’s Exchange Online infrastructure.
Exchange Online is Microsoft’s cloud-hosted email platform used by Microsoft 365 business and enterprise customers. It powers much of the email, calendar and mailbox functionality people commonly access through Outlook.
Microsoft acknowledged that users could experience degraded Exchange Online functionality, including trouble connecting to the service.
As Microsoft investigated, it discovered that the problem was larger than simply an Outlook email issue.
The company identified trouble involving an authentication component and later traced the broader disruption to a core authentication configuration used by multiple Microsoft 365 services.
In practical terms, this meant some Microsoft systems weren’t receiving or deploying the authentication components they needed as expected.
And because authentication systems sit underneath many Microsoft 365 products, the problem spread beyond email.
What Caused the Outlook Outage?
Microsoft’s official incident reporting identified the root cause as:
An issue within a core authentication configuration used by multiple Microsoft 365 services.
Microsoft also indicated during its investigation that a misconfiguration appeared to be preventing authentication components from deploying correctly to part of its infrastructure.
That’s an important distinction.
There has been plenty of speculation whenever a major cloud platform goes offline, especially around cyberattacks.
But based on Microsoft’s published information, this outage was associated with an authentication configuration and deployment problem.
There is no credible evidence in Microsoft’s incident reporting cited here that the outage was caused by a cyberattack.
Unless Microsoft later releases new findings saying otherwise, describing this as a confirmed hack would be misleading.
What Problems Did Outlook Users Experience?
The outage didn’t look exactly the same for everyone.
Some users couldn’t access their mailboxes.
Others could log in but had trouble sending or receiving email.
Microsoft and outage reports identified problems including:
- emails being delayed
- emails failing to send
- incoming messages arriving late
- authentication errors
- difficulty accessing Exchange Online
- mailbox operations failing
- Outlook search not working properly
- other workflows related to email delivery being disrupted
That explains why one person might have said, “Outlook is completely down,” while someone sitting a few desks away could still open Outlook but couldn’t search old emails.
Cloud outages are often like that.
A service doesn’t necessarily disappear entirely. Individual components can fail while others continue operating.
Outlook Search Was One of the Last Major Problems
One interesting part of this outage was the recovery sequence.
Email delivery started improving before everything else was completely back to normal.
Microsoft said Monday night that users should begin seeing a gradual recovery in mail flow as it expanded its mitigation efforts. However, Outlook search functionality remained degraded even after email service was improving.
By around 10 p.m. ET Monday, mail flow was improving but search problems remained.
Shortly after 3 a.m. ET Tuesday, Microsoft reported improvement in search functionality as well.
That’s why some users may have thought the outage was fixed while others continued reporting problems.
Both could have been correct.
Different parts of the service recovered at different times.
When Did the Microsoft Outlook Outage Start?
Microsoft’s incident information lists the service-impact start time as approximately:
Monday, August 31, 2026, at 3:08 p.m. UTC
For U.S. readers, that’s approximately:
11:08 a.m. Eastern Time
10:08 a.m. Central Time
9:08 a.m. Mountain Time
8:08 a.m. Pacific Time
Microsoft’s incident record for Exchange Online carried the identifier EX1464935, while the broader Microsoft 365 incident was identified as MO1465074.
Public outage reports began climbing around the same general period.
Downdetector data cited by the Houston Chronicle showed Outlook reports eventually reaching more than 6,000 during the outage.
Keep in mind that Downdetector figures are user reports, not a count of every affected Microsoft customer.
The true number of people impacted could therefore be significantly different.
Outlook Outage Timeline
Here’s a simplified look at how the incident unfolded.
Monday Morning, August 31
Users began reporting problems with Microsoft Outlook and Microsoft 365.
Microsoft confirmed it was investigating degraded Exchange Online functionality.
Around Midday ET
Microsoft said users could experience problems with Exchange Online and began reviewing telemetry and diagnostic data to find the source of the disruption.
Outage reports continued climbing.
Monday Afternoon
Microsoft identified an authentication component as a major contributor to the problem.
The company developed a remediation strategy and began testing it on a portion of its infrastructure before deploying the fix more broadly.
Microsoft later said the authentication issue affected services beyond Exchange Online.
Monday Evening
Microsoft’s investigation pointed toward a misconfiguration preventing authentication components from deploying as expected across part of its infrastructure.
The company began re-applying authentication components and restarting targeted sections of affected infrastructure.
Some users started seeing service recovery.
Around 7:47 p.m. ET
Microsoft said its mitigation was continuing to roll out and users should start seeing gradual recovery in mail flow.
The company was simultaneously restarting portions of infrastructure to restore downstream services.
Around 10 p.m. ET
Email delivery had improved, but Microsoft said Outlook search remained degraded for some users.
Early Tuesday, September 1
Microsoft continued restarting infrastructure and applying its authentication fix.
Shortly after 3 a.m. ET, Microsoft reported improvements in search functionality.
Tuesday Morning
Service availability continued improving.
Microsoft said its telemetry remained positive and moved into an extended monitoring period while confirming that its mitigation had reached the remaining affected infrastructure.
Latest Update
Microsoft’s public Service Health Status page now lists all products as operational.
Was Microsoft 365 Down Too?
Yes.
This was not simply an Outlook desktop-app problem.
Microsoft confirmed that the authentication issue affected multiple Microsoft 365 services.
According to Microsoft’s incident information, affected scenarios included services such as:
Exchange Online
Users could experience problems connecting to Exchange Online or sending and receiving email.
Microsoft 365 Copilot
Some Copilot requests requiring Microsoft 365 information—such as prompts involving email content—could fail.
OneDrive for Business
Some users could have difficulty loading account or storage information, syncing files or accessing certain content.
SharePoint Online
Users could experience problems loading or refreshing parts of SharePoint, searching, opening files and viewing certain information.
Microsoft Teams
Some Teams-related functions were affected, including presence and certain device-status scenarios.
Microsoft Purview
Users could encounter authorization problems, problems opening the Purview portal and delays involving certain compliance policies.
Microsoft Defender XDR
Some users could experience intermittent authorization failures.
Microsoft 365 Admin Center
Administrators could have trouble authenticating into the admin center.
Universal Print
Some users could have difficulty creating, uploading or retrieving print jobs.
This broad impact makes sense given the root of the problem.
When a shared authentication component fails, it can affect numerous services that depend on that underlying system.
Was Microsoft Teams Down?
Parts of the Microsoft Teams ecosystem were affected, but it’s more accurate to describe the incident as degraded functionality rather than saying the entire Teams platform universally went offline.
Microsoft reported issues including stale user presence information and problems with certain Teams Room devices and desktop phones appearing offline in the Teams Admin Center.
Again, that’s an important distinction.
A user may have been able to join a Teams meeting while still experiencing problems with presence or administration.
Was OneDrive Down?
OneDrive for Business was among the Microsoft 365 services affected.
Microsoft said some users could experience problems loading or refreshing parts of OneDrive and SharePoint.
Possible problems included:
- missing or stale content
- synchronization delays
- failed file opening
- search problems
- account or storage information failing to load
- operation timeouts
- problems with mobile camera uploads
- video playback issues
Microsoft specifically noted that users might experience partial failures rather than the entire platform becoming unavailable.
Was Microsoft Copilot Down?
Some Microsoft 365 Copilot functionality was affected.
The incident information indicated that Copilot prompts requiring Microsoft 365 grounding could fail.
For example, if someone asked Copilot to summarize information from their email, the underlying Microsoft 365 authentication issue could prevent the request from working properly.
This is another example of how modern cloud services are interconnected.
An email outage is no longer necessarily just an email outage.
How Many People Were Affected?
Microsoft has not publicly provided a definitive total number of users affected in the information reviewed for this article.
Downdetector reports can give us an idea of when a problem is widespread, but they shouldn’t be treated as the total number of affected users.
The Houston Chronicle reported that Outlook-related reports on Downdetector peaked at roughly 6,015 on August 31, while Microsoft 365 also received thousands of user reports.
Those figures represent people actively reporting a problem.
A company with 10,000 employees experiencing the same Microsoft 365 issue might produce only a handful of Downdetector reports—or none at all.
So the real impact can be much larger than the reporting graph suggests.
Was the Outlook Outage Worldwide?
Reports came from multiple countries, and the Microsoft 365 infrastructure affected by the incident serves customers internationally.
However, Microsoft described the impact in terms of affected infrastructure and users rather than stating that every Outlook customer worldwide was offline.
That’s why “global outage” can sometimes be too broad.
A better description is:
A major Microsoft 365 outage affecting users across multiple regions and services.
Some customers had serious problems.
Others experienced partial degradation.
And some users may not have noticed the outage at all.
Was Outlook Hacked?
There’s currently no confirmed evidence in Microsoft’s published incident information that this outage was caused by hackers.
Microsoft’s identified cause centered on a core authentication configuration and a misconfiguration affecting the deployment of authentication components.
Of course, Microsoft could release a more detailed post-incident review later.
But based on the information currently available, claims that the August 31 outage was definitely a cyberattack aren’t supported.
Why Did Outlook Take So Long to Recover?
One reason cloud-service outages can take hours to fully resolve is that fixing the original fault isn’t always enough.
Microsoft needed to re-apply authentication components across affected infrastructure and restart targeted sections of its environment.
And that had to be done carefully.
Imagine fixing a problem across a huge office building.
You don’t just flip one switch.
You’re dealing with multiple floors, systems and connected services. Some recover immediately. Others take longer.
That’s essentially what users saw here.
Mail delivery began recovering.
Then backlogged messages had to move through the system.
Meanwhile, dependent functions such as search continued experiencing residual problems.
Microsoft specifically warned users to expect delayed delivery of backlogged messages and residual impact while mitigation work continued.
Why Was Email Delayed Even After Outlook Came Back?
Think of email like traffic.
If a major highway closes for several hours, reopening it doesn’t instantly make the traffic jam disappear.
Cars that accumulated during the closure still have to move through.
The same thing can happen with email.
Messages that couldn’t immediately be processed during an outage can create a backlog.
Microsoft warned customers during the recovery that delayed delivery of backlogged messages could continue even as the underlying service improved.
So if Outlook started working again but an email sent hours earlier appeared late, that would be consistent with Microsoft’s recovery description.
What Should You Do If Outlook Is Still Not Working?
Since Microsoft’s public status page currently says services are operational, persistent problems may require troubleshooting.
Here are a few things worth trying.
1. Check Microsoft’s Status Page
Start with Microsoft’s official Service Health Status page.
If Microsoft is experiencing another major incident, that’s one of the best places to verify it.
For business and enterprise customers, administrators can also access more detailed Microsoft 365 service-health information through the Microsoft 365 Admin Center.
2. Try Outlook on the Web
If the Outlook desktop application isn’t working, try opening Outlook through a web browser.
If Outlook on the web works but the desktop application does not, the problem may be on your device rather than Microsoft’s servers.
3. Restart Outlook
Completely close the application and reopen it.
It sounds simple, but after a major service interruption, a fresh connection may resolve lingering synchronization problems.
4. Check Your Internet Connection
Try opening another website or online service.
If everything else is also failing, Outlook may not be the problem.
5. Sign Out and Sign Back In
Authentication played a central role in this outage, so refreshing your session may help if your account remains stuck with outdated credentials or tokens.
For workplace accounts, however, avoid repeatedly changing passwords unless your IT department tells you to.
6. Check With Your Company’s IT Department
If you’re using a business Microsoft 365 account, your organization’s administrator may have access to service-health information that isn’t available on Microsoft’s public dashboard.
A company-specific problem can also look exactly like a Microsoft outage.
7. Don’t Keep Resending the Same Email
This is an easy mistake.
If an email appears stuck during a service disruption, repeatedly clicking Send can eventually result in the recipient getting several copies once the system catches up.
Check your Sent folder and Outbox before trying again.
What Should Businesses Do After an Outlook Outage?
This incident is also a useful reminder for businesses that depend heavily on Microsoft 365.
Email has become so reliable that it’s easy to forget what happens when it suddenly disappears.
Companies may want backup communication options for situations like this.
That could include:
- phone
- SMS
- Slack or another messaging service
- an internal emergency communication system
- alternate email accounts for critical functions
- documented outage procedures
The goal isn’t to replace Outlook.
It’s to avoid a situation where one cloud service going down makes it impossible for employees to communicate at all.
How Can You Tell Whether Outlook Is Down or It’s Just You?
Here’s a simple checklist.
Outlook may be experiencing a broader outage if:
- coworkers are having the same problem
- multiple Microsoft 365 services stop working
- Microsoft acknowledges an incident
- outage-reporting sites show a sudden large spike
- users across different networks and devices experience similar problems
The problem may be on your side if:
- Microsoft shows everything operational
- your coworkers can use Outlook normally
- Outlook works on your phone but not your computer
- Outlook on the web works but the desktop app does not
- your internet connection is unstable
- only one account is affected
Checking these things can save you from spending an hour reinstalling Outlook during a Microsoft-wide outage—or waiting for Microsoft to fix something that’s actually happening only on your computer.
Outlook Outage 2026 FAQ
Is Microsoft Outlook down today?
Microsoft’s public service-health page currently shows all products operational. The major outage that began August 31 has substantially recovered.
When did the Outlook outage start?
Microsoft’s incident data lists the impact as beginning August 31, 2026, at approximately 3:08 p.m. UTC, or 11:08 a.m. Eastern Time.
What caused the Outlook outage?
Microsoft identified an issue involving a core authentication configuration used by multiple Microsoft 365 services. The company also said a misconfiguration interfered with authentication-component deployment across part of its infrastructure.
Was Exchange Online affected?
Yes. Exchange Online was the service most prominently affected, with users experiencing email, connection, authentication and search problems.
Were emails lost?
Microsoft described delayed and failed email delivery and warned about a backlog during recovery. The information reviewed for this article does not establish widespread permanent email loss.
Why wasn’t Outlook search working?
Search remained degraded after mail flow started recovering. Microsoft continued applying its authentication fix and restarting affected infrastructure, and search functionality subsequently showed improvement early Tuesday.
Was Microsoft Teams affected?
Yes, certain Teams-related scenarios were affected, including presence information and some Teams Room and device-management functions.
Was OneDrive affected?
Yes. Some OneDrive for Business and SharePoint Online users experienced loading, synchronization, search and file-access issues.
Was Microsoft Copilot affected?
Some Microsoft 365 Copilot prompts that depended on Microsoft 365 content could fail during the outage.
Was the outage caused by a cyberattack?
Microsoft’s published incident information attributes the problem to authentication configuration and deployment issues. There is currently no confirmed information in those reports identifying a cyberattack as the cause.
Is Microsoft Outlook fixed now?
Microsoft’s public Service Health Status page currently says all products are operational.
Final Thoughts: Outlook Is Back, but the Outage Shows How Much We Depend on Microsoft 365
For millions of people, Outlook isn’t just an email app.
It’s where work happens.
It’s meeting invitations, client conversations, calendars, attachments, approvals, customer communications and years of searchable business history.
That’s why an outage like the one that began August 31 becomes noticeable very quickly.
Microsoft traced the disruption to a core authentication configuration problem that affected Exchange Online and several other Microsoft 365 services. The company spent hours testing fixes, re-applying authentication components and restarting portions of affected infrastructure. Email delivery gradually recovered, while downstream functions such as Outlook search took longer to stabilize.
The most important update now is positive:
Microsoft’s public status page currently lists all products as operational.
So the broad outage appears to be over.
If Outlook is still failing on your computer or phone, it’s now worth checking whether the problem is specific to your account, device, network or organization rather than assuming Microsoft 365 remains broadly unavailable.
And if there’s one lesson from the outage, it’s that even the cloud services we barely think about can suddenly remind us just how much of the modern workday depends on them.
When Outlook disappears for a few minutes, it’s annoying.
When email, search, authentication, OneDrive, SharePoint and other connected services start having problems at the same time, the impact becomes much bigger very quickly.
For now, though, Microsoft says its services are operational again.
