Go to any Office app and ensure you’re signed in with the same Microsoft account linked to your license. Remove and re-add your account under the "Account" settings of the app if needed. If this doesn’t work, reset the credentials in your Windows Credential Manager Outlook Login Issues Troubleshooting or contact Microsoft support for further assistance. Despite its robust feature set and user-friendly design, it’s not uncommon for end users and IT professionals to encounter sign-in and activation issues. 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. Yes, Microsoft 365 works offline for most apps like Word and Excel.

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

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. Clearing cached credentials, running a repair, or using the Microsoft Support and Recovery Assistant (SaRA) can also address common local device issues. Verify that you’re logged into Outlook Not Sending or Receiving Email the correct Microsoft account both in OneDrive and Office apps. If syncing is paused, resume it from the OneDrive system tray icon.

Recover your account

The Microsoft Support and Recovery Assistant can automate fixes for common error codes. The "Unlicensed Product" error usually indicates an inactive or unlinked subscription. Confirm your subscription status and sign in with the correct Microsoft account. Run the Activation Troubleshooter, accessible online or via your app settings.

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.
• 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.
• 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.

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 credential loop in Microsoft 365 once a connection is re-established.