Error when creating the AA_Admins Local SQL group when a MSSQLSERVER instance (4340027)

When running the Configuration Wizard and creating a new Database or Archive Database the error "Unable to create Windows group ""AA_Admin" on the Target machine" may be displayed 

This can happen when using a Default instance of SQL such as ComputerName/MSSQLServer,port but not using it when selecting the database server. 

you have the option to enter a Database Server  or Browse. In this example Customer has ComputerName/MSSQLServer,port.  Server | Default Instance| CustomPort.  If you just add the SQL computer name this fails as you need to add the port, If you add the port and browse the picker only shows the ComptuerName,Port To select, It does not show the Default Instance. (It will show other Named Instances). If you select this as it will allow you to continue and does create the database, however (by default) it attempts to create the AA_Admins and AA_User local group on the SQL Server. It will use the details provided "ServerName,port" and fail, as the actual name is "ServerName" Not ServerName,port . It Looks like our software expects what you enter to be a cmputername unless you add the / for the SQL instance.  Would like to see an example in this screen stating to enter  to use ServerName/Instance,port and that you need to always specify the instance even if it is the default MSSQLSERVER and to add the port if not default

Resolution:

Please Use "ComputerName/MSSQLServer,port" even on default instances.