Assume that you use Microsoft SQL Server 2017 on a Linux host that is joined to an Active Directory child domain. When you try to create a login that is based on a Windows domain user that belongs to the parent domain, you may receive an error message that resembles the following:
Msg 15401, Level 16, State 1
Windows NT user or group user_name not found. Check the name again.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.