changing range to range in row immediately below in a loop

my objective is to do data validation for all cells in columns B through E in which there is a value in column A. i am able to get it to do the first row, but when it comes to changing the range to be used (B:E) i cannot seem to get it to adjust for the row that it is in. i think the fix is relatively simple i just cannot think of it. any ideas?

Dim i, n As Integer

n = Range("A:A").Cells.SpecialCells(xlCellTypeConstants).Count
n = n - 1

Range("B2").Select

Dim ran As Range


    Do While IsEmpty(ActiveCell.Offset(0, -1)) = False

      With ActiveCell.Validation
        .Delete
        .Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:= _
        xlBetween, Formula1:="=$N$2:$N$3"
        .IgnoreBlank = True
        .InCellDropdown = True
        .InputTitle = ""
        .ErrorTitle = ""
        .InputMessage = ""
        .ErrorMessage = ""
        .ShowInput = True
        .ShowError = True
         End With
    
    Selection.AutoFill Destination:=Range("B:E"), Type:=xlFillDefault
    ActiveCell.Offset(1, 0).Select

    Loop