Outlook won't open on computer or phone

Question

Outlook won't open on computer or phone

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Is outlook down? I can't open outlook on my phone or on my main computer

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2 answers

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Answer 1

Check Microsoft’s live Service Health Status first, because Outlook failing on both the phone and computer can indicate a service incident rather than a problem with either device.^1^

Determine whether Outlook is down

Open the Service Health Status link from Microsoft’s Outlook.com issues page.^1^
Look for an active Outlook.com incident or service degradation.
If an incident is shown, no device repair is needed. Monitor that page and retry after Microsoft reports recovery.

The information available here cannot confirm the live service state at this exact moment; the status page is the authoritative current check.

If no outage is listed

Test the web mailbox independently of both Outlook apps:

On the computer, open an InPrivate/Incognito window.
Go directly to https://outlook.live.com/mail/.
If it works privately, clear cookies and cached data for Outlook/Microsoft sites, temporarily disable browser extensions or ad blockers, and retry in a supported browser.^2^
On the phone, turn off Wi-Fi and test through mobile data. This distinguishes an account/service issue from a shared home-network problem.

If the mobile app itself crashes:

Android: Settings → Apps → Outlook → Force stop, then Storage → Clear cache. Update Outlook afterward.
iPhone/iPad: close Outlook from the app switcher, restart the device, update Outlook, and—if necessary—use Settings → General → iPhone Storage → Outlook → Offload App. Offloading preserves the app’s documents and data.^3^

If it still fails everywhere

If no incident is listed and the mailbox fails in an InPrivate window on the computer and over mobile data on the phone, contact Outlook.com support. If Outlook.com opens, select Help, enter the problem, then scroll to Still need help? → Yes. Microsoft also provides a separate contact option when sign-in is impossible.^4^

Record the exact error message, timestamp, and whether the failure occurs before or after sign-in; support will need those details.

References

Answer 2

Welcome to Microsoft Q&A!

Hello,

What you are experiencing is currently linked to an active Microsoft 365 service incident tracked under ID EX1550543.

Microsoft initially reported intermittent connectivity issues affecting Exchange Online mailboxes in the Americas, and has since updated the advisory to confirm that the issue may impact general Microsoft 365 service connectivity across any region.

What this means for your environment:

Affected Services: Primarily Exchange Online / Outlook (desktop client, Outlook on the web, and mobile apps), along with potential authentication or connection timeouts across broader Microsoft 365 services (such as Teams, SharePoint/OneDrive, or the Microsoft 365 Admin Center) that rely on shared front-end connectivity infrastructure.

Action Required: No configuration changes are needed on your tenant or client devices. Microsoft engineering teams are actively working on mitigation.

How to track live status:

Open the Microsoft 365 Admin Center using a Global Admin or Service Support Admin account.

Navigate to Health > Service health.

Search for incident ID EX1550543 for real-time mitigation progress and root cause updates.(You can also follow official updates via @MSFT365Status on X).

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