Upgrade a trial to a full server licence
Enter in an elevated command prompt the following:
Dism /online /Set-Edition:ServerStandard /AcceptEula /ProductKey:12345-67890-12345-67890-12345
Of course you have to enter your correct Product Key 😎
Enter in an elevated command prompt the following:
Dism /online /Set-Edition:ServerStandard /AcceptEula /ProductKey:12345-67890-12345-67890-12345
Of course you have to enter your correct Product Key 😎