Windows Server 2019, The product key you entered didn't work. Check the product key and try again, or enter a different one. (0x80070490)

Open a command prompt as administrator.

Run-

c:\windows\system32\slmgr.vbs /ipk <product_key>

OR

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