"Error 7q6ca" with Code 2147483661.

First verify whether the license appears in the Microsoft account and whether that account signs in successfully through a browser, because error 7q6ca / 2147483661 alone does not distinguish a licensing problem from a Windows desktop sign-in failure.

1. Separate licensing from desktop sign-in

1. Close all Office applications.
2. Open the Microsoft account → Services & subscriptions page and sign in with the personal Microsoft account used to purchase or redeem Office.
3. Check whether Microsoft 365, Office Home, or the corresponding Office product appears:
   • Product is listed and active: continue to section 2.
   • Product is missing: try any other personal account that might have been used for the purchase.
   • Subscription is expired: renew it before retrying activation.
   • Unused product key: redeem it once through Office.com/setup, which attaches the product to the Microsoft account.^1^
4. Using the same account, test signing in at Office.com:
   • If browser sign-in also fails, resolve the Microsoft account sign-in problem first.
   • If browser sign-in works but Word or Excel produces 7q6ca, proceed as a Windows desktop-authentication issue. The same error/code combination has been reported in that scenario.^2^

2. If browser sign-in works but desktop Office fails

Run the Microsoft 365 sign-in troubleshooter on the affected PC:

1. Open Start → Get Help.
2. Search for sign in to Microsoft Office.
3. Run the offered sign-in troubleshooter and apply its recommendations.
4. Restart Windows and test Word again.

Then remove stale Office credentials:

1. Open Start, search for Credential Manager, and select it.
2. Select Windows Credentials.
3. Expand and remove entries named MicrosoftOffice16.
4. Open Settings → Accounts → Access work or school.
5. If an obsolete account is listed there, select it and choose Disconnect. Do not disconnect the account currently required by an employer or school.
6. Restart Windows and sign in to Office again.^3^

3. Conditional personal-account sign-in package repair

Use this only when:

• The personal Microsoft account works in a browser;
• Desktop Office authentication still fails;
• The PC runs Windows 10 version 1703 or later; and
• The installed product is Microsoft 365 version 1807 or later.

Open Windows PowerShell as administrator and run:

if (-not (Get-AppxPackage Microsoft.Windows.CloudExperienceHost)) {
    Add-AppxPackage -Register `
      "$env:windir\SystemApps\Microsoft.Windows.CloudExperienceHost_cw5n1h2txyewy\Appxmanifest.xml" `
      -DisableDevelopmentMode -ForceApplicationShutdown
}
Get-AppxPackage Microsoft.Windows.CloudExperienceHost

This re-registers the Windows Live ID package used for personal Microsoft-account authentication. Restart Windows afterward and retry Office activation.^4^

4. If authentication works but Office remains unlicensed

1. Open Control Panel → Programs → Programs and Features.
2. Search for Office.
3. If multiple Office versions are installed, uninstall only the version you no longer use, then restart.
4. If one installation remains, select it, choose Change, and run Online Repair.
5. Restart and sign in using the account shown under Services & subscriptions.

Multiple installations can conflict with activation, and Microsoft recommends Online Repair if activation still fails after removing the unused installation.^5^

If none of these resolves it, contact Microsoft Support and provide the complete error text, Tag 7q6ca, Code 2147483661, the timestamp/correlation ID shown in the dialog, Windows version, Office edition, and whether browser sign-in succeeds. Do not post the correlation ID publicly.

References

1. Activate Office for Windows | Microsoft Support
2. I cannot login into my Office 365 desktop applications - Microsoft Q&A
3. Sign in issues when activating Microsoft 365 Apps
4. Fix authentication issues in Microsoft 365 apps when you try to connect to a Microsoft 365 service
5. Unlicensed Product and activation errors in Office | Microsoft Support