When Outlook will not open, Teams stops connecting, or OneDrive refuses to sync, most people jump straight to the worst-case scenario. Is Microsoft 365 down? Is the office internet broken? Did the computer just decide today was the day to quit?
The good news is that you can usually narrow the problem down in just a few minutes. A simple troubleshooting flow helps you decide whether to wait, fix something locally, or call for support. For small businesses, that can save time, reduce panic, and keep staff from making unnecessary changes while a larger outage is already being handled elsewhere.
Start by asking who is affected
The first question is simple: is it just one person, or are multiple users having the same issue?
If one employee cannot access Outlook but everyone else is working normally, the problem is more likely tied to that user’s computer, password, internet connection, or app profile. If several people in the same office suddenly cannot sign in to Teams or open SharePoint, the issue may be broader.
This quick check matters because it changes your next step. Widespread problems usually point to a service issue or a network problem. Single-user problems usually point to something local.
Before going any further, ask:
- Are coworkers seeing the same issue?
- Are users in other locations affected too?
- Did the problem start at the same time for everyone?
If the answer is yes, pause before changing settings on individual computers.
Test another device or connection
A fast way to separate a device problem from a service problem is to try another device.
For example, if Outlook is failing on a desktop, check whether the same account works on a phone or another laptop. If Teams will not load on office Wi-Fi, try a mobile hotspot. If OneDrive is not syncing on one machine, sign in through the web browser.
This helps answer an important question: is the service reachable at all?
If Microsoft 365 works on another device, the issue is probably local to the original computer. That could mean an outdated app, a corrupted sign-in session, cached credentials, or a network setting on that device. If it fails everywhere, the issue may be with the internet connection, the office network, or Microsoft’s side.
Confirm basic internet access
Sometimes Microsoft 365 is blamed for a problem that actually starts with connectivity.
If Outlook, Teams, and SharePoint all seem unavailable, test a few non-Microsoft websites and cloud services. If nothing is loading, the problem may be your ISP, firewall, router, or office network. If the internet works normally but Microsoft 365 apps do not, keep digging.
It is also worth checking whether the issue affects only wired devices, only Wi-Fi users, or only remote staff on VPN. Patterns like that often point to a network path issue rather than a full Microsoft outage.
Microsoft also provides a network connectivity test at connectivity.office.com/status, which can help identify connection quality and routing issues affecting Microsoft 365 services.
Check Microsoft 365 service health
Once you know the internet is working, check whether Microsoft is already reporting a problem.
For business tenants, the best source is the Microsoft 365 admin center service health dashboard. Microsoft documents that admins can review active incidents and advisories under Health > Service health in the admin portal. If admins cannot sign in, Microsoft also provides a public service status page at status.cloud.microsoft.
Third-party sites can also help confirm whether a problem is widespread:
These community-driven sources are useful for spotting patterns quickly, but they should support your troubleshooting, not replace official Microsoft information. A spike in reports may indicate a real issue, but it can also reflect regional or isolated problems.
Do not overlook password or MFA changes
Not every “Microsoft 365 outage” is an outage.
If a user recently changed their password, updated multi-factor authentication, got a new phone, or lost access to an authenticator app, that can break sign-in for Outlook, Teams, OneDrive, and other Microsoft 365 services all at once. From the user’s perspective, it can look exactly like Microsoft is down.
Check for:
- Recent password resets
- MFA prompts that are not being approved
- Old saved credentials on the device
- Sign-in blocks caused by security policies or conditional access
In many cases, reauthenticating the account or updating saved credentials resolves the issue faster than reinstalling apps or rebooting repeatedly.
A simple decision flow for businesses
When Microsoft 365 appears to stop working, use this order:
- Check whether one user or many users are affected.
- Test another device or another internet connection.
- Confirm basic internet access.
- Review Microsoft 365 service health.
- Check for recent password or MFA changes.
That process helps you avoid guesswork. If Microsoft is having a known issue, you can wait and monitor updates. If only one user is affected, you can focus on that device or account. If the office network is the problem, you can troubleshoot locally or contact your IT provider with better information.
When Outlook, Teams, OneDrive, or SharePoint stop working and you are not sure what to trust, Illini Tech Services can help businesses across central Illinois figure out whether the problem is Microsoft, the local network, or the computer in front of you. Call 217-854-6260 or email [email protected] to get help quickly and avoid unnecessary downtime.