License Activation

Hello Hubert Kowalski,

This specific error message, "Can't activate Windows by phone," indicates that the specific policy setting allowing telephone activation has been disabled on the local machine, usually via the slui.exe interface restrictions. Even if your domain policies appear clean, this setting can persist as a local Group Policy object or a registry tattoo from a generalized image or a previous configuration script, specifically affecting the Software Protection Platform. Since troubleshooting the GUI stack can be time-consuming and you need to get the server licensed, the most direct solution is to bypass the graphical interface entirely and interact directly with the licensing service via the command line.

You can complete the phone activation process manually using the Software Licensing Management Tool (slmgr). Open an elevated Command Prompt or PowerShell and run the command slmgr /dti. This will display your Installation ID (IID) in a pop-up window without triggering the blocked UI. Take this IID and call the Microsoft Activation Center for your region (or use the mobile self-service activation site if available). Once the automated system validates your IID and reads back the Confirmation ID (CID), return to your command prompt. Enter the command slmgr /atp <ConfirmationID> (replace <ConfirmationID> with the string of numbers you received, with no spaces). After the command executes successfully, run slmgr /dli to verify that the license status has changed to "Licensed."

Regarding the root cause of the UI block, if you wish to restore the graphical functionality for future use, you should inspect the registry directly rather than relying on GPO reports, as local overrides often hide there. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SoftwareProtectionPlatform\Activation. Look for a DWORD value named DisablePhone. If this value exists and is set to 1, it is suppressing the phone activation option. Deleting this key or changing the value to 0 will restore the slui 4 functionality.

I hope you've found something useful here. If it helps you get more insight into the issue, it's appreciated to accept the answer. Should you have more questions, feel free to leave a message. Have a nice day!