Formula won’t calculate or increment

In the following code, my formula apply as text and won’t calculate. Also, Autofill won’t increment cell number. I also tried with ActiveCell.Value

Dim RowCount As Variant
Dim VRowStartNoMember As Variant
Dim FirstBlankCell As String
Windows("Compliancy_Previous.xlsm").Activate
Sheets("Previous").Select
RowCount = Range(("F1"), Range("F1").End(xlDown)).Rows.Count
    
    Range("A2").Select
    If IsEmpty(Range("A2").Value) = False Then
    Range("A2").End(xlDown).Offset(1, 0).Select
    End If
    VRowStartNoMember = ActiveCell.Row
    FirstBlankCell = "F" & VRowStartNoMember
    ActiveCell.Formula = "=IFERROR(VLOOKUP(FirstBlankCall,Import!A:E,2,0),"""")"
    ActiveCell.AutoFill Destination:=Range(ActiveCell.Address & ":A" & RowCount)