Use the Microsoft 365 network connectivity test to measure connectivity between your device and the internet, and from there to Microsoft’s network. Use the MIcrosoft 365 inventory scan troubleshooter to generate either a normal troubleshoot Outlook synchronizing folders error or full scan report of your computer and installed Microsoft 365 applications. Use the Microsoft 365 sign-in troubleshooter to help resolve sign-in issues encountered with Microsoft 365. If you can't sign into your Microsoft account, most issues can be identified by our sign-in helper tool.

How do I fix the ‘Product Activation Failed’ error in Microsoft 365?

Additionally, ensure you’ve installed all available updates, as performance improvements are often included in patches. Regularly cleaning up your hard drive or upgrading hardware like RAM can also enhance performance. If you’ve tried all these steps and still can’t resolve the sign-in or activation errors, you may need more advanced troubleshooting. Completing the above steps resolves a large majority of reset cached Exchange mode typical sign-in and activation problems.

Recover your account

Office 365 uses several internet endpoints and cloud services to authenticate users and validate licenses. If these connections are disrupted, sign-in and activation will fail. Use the Excel check troubleshooter to resolve Excel for Windows startup, hang, or crash issues. Get Help has troubleshooters for Microsoft 365 you can run for many common scenarios. These often help resolve issues without the need to contact support. If a troubleshooter is available for your issue, select Start to run that troubleshooter.

3 Step 3: Verify Network Connectivity and Firewall Settings

• For codes linked to storage limitations, free up disk space or install on an external drive.
• Double-check your internet connection, as OneDrive requires an active network to sync files properly.
• Use the Microsoft 365 shared computer activation (SCA) troubleshooter to enable shared computer activation for Microsoft 365 applications.
• The "Unlicensed Product" error usually indicates an inactive or unlinked subscription.
• You'll have the option to do that on your \"My Questions\" page if you choose to rate our interaction or you can request me by name if you wish.
• Office 365 uses several internet endpoints and cloud services to authenticate users and validate licenses.
• And if your environment is particularly security-conscious, keep in mind that policy-based blocks on specific devices or geographic regions can also interfere with Office activation.
• If you would like to ask me another question in the future, you can add me as a favorite Expert.
• Keep cache sizes clear and refer to official Microsoft troubleshooting manuals for persistent app freezes.

You might find it simple, but the most common cause of login failure is entering the wrong username and password combinations. Below is a structured approach to diagnosing and resolving Office 365 sign-in or activation errors. Start with the basics and move toward more advanced methods only if necessary.

Microsoft 365 Troubleshooting – Quick Fixes for Common Problems

Understanding these root causes will help you map out a clearer resolution path. In many cases, performing simple checks—like verifying correct usernames and valid licensing—will resolve the issue quickly. After you run any troubleshooter, Get Help provides details on any findings and suggestions for possible remedies. Outlook data file cannot be accessed If one of these resolves your problem, close the app and continue working. Use the Microsoft 365 shared computer activation (SCA) troubleshooter to enable shared computer activation for Microsoft 365 applications.