The error could appear as either of the following depending upon where you encounter it:

Windows is unable to reach your company’s activation service. Please connect to your corporate network. If you are connected and continue to see the error, contact your system administrator. You can also click on the error detail to find the exact error. Error code: 0xC004F074.Activating Windows(R),(Key hash)…Error: 0xC004F074 The Software Licensing Service reported that the computer could not be activated. No Key Management Service (KMS) could be contacted.Please see the Application Event Log for additional information.Error 0xC004F078,  SL_E_AUTHN_MISMATCHED_KEY, The Software Licensing Service reported that the key is mismatched.

Windows Activation error 0xC004F078

If you cannot activate Windows 11/10, then here are some method to fix the Windows Activation error 0xC004F078:

1] Use the correct key for your type of Windows copy

Check the type of your Windows copy – Is it OEM, Retail or Volume? – and ensure that you are using the correct, valid product key for your system.

2] Use Command Prompt to reinstall the key

Run the Command Prompt as Administrator. Now execute the following commands: To uninstall the existing key, enter:

To install the KMS Product Key, enter:

Once done, you will get a prompt whether the operation was either successful or not. To activate it online, type: To activate it using the telephone, type: After activating the KMS key, restart the Software Protection Service. You can then also verify the Activation Status to check if your fix was successful or not. Read: Troubleshoot KMS Activation on Windows Server.

3] Use the Activation Troubleshooter

You can run the Activation troubleshooter. The Windows Activation Troubleshooter will help you address most commonly encountered activation issues on Genuine Windows devices including those caused by hardware changes. Hope these fixes have helped you. Links that may help you: