This also failed for us but may have been due to not having enough requests to meet the activation threshold (25) on the KMS server.

CSCRIPT "%WINDIR%\system32\slmgr.vbs" /skms yourkmsservername:1688

CSCRIPT "%WINDIR%\system32\slmgr.vbs" /ipk 33PXH-7Y6KF-2VJC9-XBBR8-HVTHH

CSCRIPT "%WINDIR%\system32\slmgr.vbs" /ato

You might also try this on your golden image and then recompose:

1. regedit HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\vmware-viewcomposer-ga, change SkipLicenseActivation to 0
2. If slmgr /dlv shows 0 rearm count then regedit HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SoftwareProtectionPlatform, change SkipRearm to 1
3. regedit HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\activation\manual  to 0 and NotificationDisabled to 1

The scripts run as the system user. If you use a proxy server, the system user might need to have a proxy specified:

NETSH winhttp SET proxy yourproxyservername:andport

CSCRIPT "%WINDIR%\system32\slmgr.vbs" /skms yourkmsservername:1688

CSCRIPT "%WINDIR%\system32\slmgr.vbs" /ipk 33PXH-7Y6KF-2VJC9-XBBR8-HVTHH

CSCRIPT "%WINDIR%\system32\slmgr.vbs" /ato

NETSH winhttp reset proxy