You can feel free to contact our experts, as they are available 24X7 for solving your issues. If your subscription has expired, your account is disabled, or your IT admin has blocked your account, in all these cases, you would not be able to log in to your account. Use the Microsoft 365 setup troubleshooter to install Microsoft 365, Office 2021, Office 2019, or Office 2016 on your Windows PC. Use the uninstall troubleshooter to uninstall Microsoft 365, Office 2021, Office 2019, or Office 2016 from your Windows PC.

Common Causes of Office 365 Sign-In and Activation Issues

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 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.

I can't sign in to my Microsoft account

In this comprehensive guide—KB113—we’ll explore the most common causes of Office 365 sign-in and activation issues. We’ll then walk you through a practical, step-by-step troubleshooting methodology. Combine these best practices with ongoing training and proactive license management, and you’ll be well on your way to a stable, secure Office 365 environment. Sometimes, an expired license or outdated credentials are the culprit. Other times, it might be network problems, conflicting versions of Office, or organizational security policies that block the authentication process.

What should I do if updates for Microsoft 365 apps fail to install?

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 the correct Microsoft account both in OneDrive and Office apps. If syncing is paused, resume it from the OneDrive system tray icon.

Frequently asked questions

If this doesn’t work, reset repair PST file without data loss the credentials in your Windows Credential Manager 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.

• Clearing cached credentials, running a repair, or using the Microsoft Support and Recovery Assistant (SaRA) can also address common local device issues.
• Use the Microsoft 365 network connectivity test to measure connectivity between your device and the internet, and from there to Microsoft’s network.
• In this guide, we will take an in-depth look at troubleshooting and resolving common Microsoft 365 login problems so you can keep your business running smoothly.
• Start with the very basic checks and move to the more complex troubleshooting tips.
• Make sure your phone’s operating system is supported by Microsoft 365.
• Completing the above steps resolves a large majority of typical sign-in and activation problems.
• Use the Microsoft 365 setup troubleshooter to install Microsoft 365, Office 2021, Office 2019, or Office 2016 on your Windows PC.
• For work or school accounts, confirm with your organization that your account is active.

Yes, Microsoft 365 works offline for most apps like Word and Excel. 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 once a credential loop in Microsoft 365 connection is re-established. Always verify offline availability settings for critical documents you might need.



According to a recent report, approximately 60% of Microsoft 365 users have experienced login issues at least once in the past year. This shows that the problem is widespread and it is affecting millions of users worldwide. For more advanced or persistent cases, reviewing Azure AD sign-in logs, double-checking MFA setups, or investigating Conditional Access policies may be necessary. 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 the license is valid and assigned correctly, the next steps involve checking network-related blocks and performing initial device-level troubleshooting.

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

Repair your Office installation through "Programs and Features" using its built-in fix tool. If freezing persists, reinstall the app using files downloaded from your account dashboard to rule out bugs. Keep cache sizes clear and refer to official Microsoft troubleshooting manuals for persistent app freezes.

Confirm your subscription status and sign in with the correct Microsoft account. Run the Activation Troubleshooter, accessible online or via your app settings. Verify your device is connected to the internet and your payment details are recreate Outlook profile step by step current for renewal.