You may get the following error while promoting the machine to a domain controller. Below is the complete error with its solution.
The Error Message:
Verification of prerequisites for Domain Controller promotion failed. The local Administrator account becomes the domain Administrator account when you create a new domain. The new domain cannot be created because the local Administrator account password does not meet requirements. Currently, a password is not required for the local Administrator account. We recommend that you use the net user command-line tool with the /passwordreq:yes option to require a password for this account before you create the new domain; otherwise, a password will not be required for the domain Administrator account.
Execute the following command on Powershell.
net user Administrator /passwordreq:yes