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 guide to Office 365 sign-in errors 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?

If we don't detect any problem, we'll guide you through how you can help yourself. Being a Microsoft 365 user, if you have encountered an error while logging into your account, you are not alone. Remember, if all else fails, reaching out to Microsoft Support directly or using their official support documentation can provide tailored assistance for complex organizational setups. With the right planning and knowledge, nearly all sign-in and activation troubles can be resolved quickly and efficiently. Sometimes cached credentials on your device or a corrupted Office profile can lead fix MFA prompts not working to repeated sign-in prompts or activation failures.

Recover your account

If the issue persists, Microsoft has created a dedicated tool called Microsoft Support and Recovery Assistant (SaRA) to automate many troubleshooting tasks. The tool will ask you to enter the email address or mobile phone number you're trying to sign in with and check the details you provide. If we detect a problem with your account, we'll tell you what you need to do to solve the problem.

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.
• 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.

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

Simply open the Office app normally, and all your files are saved locally until internet access resumes. For cloud-based services like Outlook or OneDrive, offline access won’t work until you sync online again. Make sure to save any updates for immediate syncing work offline mode stuck once a connection is re-established.