By using a new activation key on the KMS server, which also supports Windows Server 2022 and Windows 11, no Windows Desktop LTSC versions (Windows 10 2015 LTSC, Windows 10 2016 LTSC, Windows 10 2019 LTSC, ...) could be activated. Windows Desktop (annual/semi-annual) Education and Enterprise versions were NOT affected (see our incident report, opens an external URL in a new window).
To date, neither a solution nor a workaround has been found by Microsoft. Therefore, TU.it has now implemented a workaround and released it with immediate effect.
The activation problem can be solved by updating the activation script to at least version 18.104.22.168. The update can be done within the activation script by using the link on the bottom left or by using the TUtoolbox.