Windows Server 2019 (and 2016) Evaluation Product Key Activation Error

When activating Windows Server 2019 (Standard or Datacenter) installed with an Evaluation ISO, you receive an error

The product key you entered didn't work. Check the product key and try again, or enter a different one. (0x80070032)

The solution is to activate via console (cmd.exe). This method should also work for Windows Server 2016.

1. First get the target edition

   Dism /online /Get-CurrentEdition

2. Next provide the target edition in the below command using the output from the previous step. In this example the target edition was: ServerDatacenter

   DISM /online /Set-Edition:ServerDatacenter /ProductKey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX /AcceptEula

3. You should then see Removing package Microsoft-Windows-… which may take a while. If after a few minutes it is not progressing / freezes / hangs – right click in the window or press Control + D and restart the same command.
4. Once the package is removed, the system should ask for a reboot and then configure updates to complete the process.