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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 Outlook Stuck on Synchronizing Folders 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 repair PST file without data loss 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
- If you or your employees can’t sign in to Office 365, or if the applications repeatedly prompt for activation, productivity can grind to a halt.
- Confirm your subscription status and sign in with the correct Microsoft account.
- Use the Microsoft 365 setup troubleshooter to install Microsoft 365, Office 2021, Office 2019, or Office 2016 on your Windows PC.
- By verifying the basics—correct credentials, valid license assignments, and stable network access—you’ll often fix the issue without delving into more complex solutions.
- Larger files may cause a temporary slowdown, so ensure your device has adequate memory.
- Slow performance can be due to heavy CPU usage or low available memory.
- Start with the basics and move toward more advanced methods only if necessary.
- If your account is locked due to multiple unsuccessful login attempts, wait for the lockout period to end.
- In many cases, performing simple checks—like verifying correct usernames and valid licensing—will resolve the issue quickly.
Follow this guide to ensure a smooth and error-free Microsoft 365 login experience. Additionally, check out the above-listed security best practices and keep your team members aware of common troubleshooting tips. Troubleshooting Microsoft 365 login issues often requires a methodical approach, starting with basic checks and escalating to more complex troubleshooting if needed. Remember, proactive management and regular reviews of your IT infrastructure can prevent many common issues, keeping your business operations running smoothly. Make sure your phone’s operating system is supported by Microsoft 365.
Microsoft 365 Troubleshooting – Quick Fixes for Common Problems

Look up the error code on the official Microsoft site for tailored steps. fix Outlook after Windows update issues Check if your system meets the Microsoft 365 installation prerequisites. For codes linked to storage limitations, free up disk space or install on an external drive.