If it doesn't work and getting an error like: Error: 0xC004F069 or Error 1168 the specified product key could not be validated, You need a Retail product key (which you will get if purchased from us) and use DISM command to upgrade Windows Server Edition from evaluation edition to Standard or Datacenter edition.
Sometimes you may need to uninstall the previous key by this command: slmgr /upk
Please be sure that your server is running Up to Date on the current version, so complete all update before the conversion!! For this issue, please check this link to be sure about your server version and the current version or use the following both command on PowerShell/Command Prompt - Run as Administrator:
Type following command on command prompt or PowerShell/Windows Terminal to upgrade your Windows Server Standard or Datacenter evaluation version to Retail version.
Standard Edition: DISM /Online /Set-Edition:ServerStandard /ProductKey:xxxxx-xxxxx-xxxxx-xxxxx-xxxxx /AcceptEula
Datacenter Edition: DISM /Online /Set-Edition:ServerDatacenter /ProductKey:xxxxx-xxxxx-xxxxx-xxxxx-xxxxx /AcceptEula
Click Y and restart the system and it's done. Please note: This method only work with Retail License for upgrading from Windows Server Evaluation version to Retail & Licensed version. If you purchased from us and going to implement your server on the environment by our given Server OS and License, simply skip it. It's only required for whom, who already installed Windows Server Evaluation version.
Still have the issue? Please use/install the Generic Volume License Keys (GVLK) at first which you will get from this link, and take a restart of your server and then try again with your purchased Retail License which you will get from us(if purchased from us) or from another retail seller. Otherwise you can contact with Microsoft Support also for fixing the issue.
If the server is running an evaluation version of Windows Server Standard/Datacenter as Domain Controller, you can convert it to a retail version as follows:
If the server is a domain controller, you cannot convert it to a retail version. In this case, install an additional domain controller on a server that runs a retail version and remove AD DS from the domain controller that runs on the evaluation version. For more information, see https://technet.microsoft.com/library/hh994618.aspx.
Read the license terms.
From an elevated command prompt, determine the current edition name with the command DISM /online /Get-CurrentEdition. Make note of the edition ID, an abbreviated form of the edition name. Then run DISM /online /Set-Edition:<edition ID> /ProductKey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX /AcceptEula, providing the edition ID and a retail product key. The server will restart twice. Example: DISM /Online /Set-Edition:ServerDatacenter /ProductKey:xxxxx-xxxxx-xxxxx-xxxxx-xxxxx /AcceptEula
For the evaluation version of Windows Server Standard, you can also convert to the retail version of Windows Server Datacenter in one step using this same command and the appropriate product key. For more information about Dism.exe, see https://go.microsoft.com/fwlink/?LinkId=192466.
Nothing works? Please use the Generic Volume License Keys (GVLK) first which you will get from this link, and take a restart of your server and then try again with your purchased Retail License which you will get from us(if purchased from us) or other Microsoft Partner/Seller. Otherwise you can contact with Microsoft Support also for fixing the issue as you will have a genuine license for activation.
Seems like complicated? Why not reinstalling the server over your current server? It will give you an option to keep old data while installing the server.