Run time error 1004 and i cant figure out why??

hey everybody.
Okay so Im having issues with trying to save my invoice sheet as a new workbook. i have got it so i can change my invoice number since its just invoices. but when i try and run a macro that is supposed to save the sheet as a new workbook it comes up with runtime error 1004 and tells me to check a bunch of stuff and after going through it all i cant figure it out. please help me out.

p.s. this is the code im using and the bold part is what gets highlighted when i debug.

Sub SaveInvWithNewName()
    Dim NewFN As Variant
    Dim sfile As String
    ' Copy Invoice to a new workbook
    ActiveSheet.Copy
    NewFN = "C:\Users\Owner\Documents\roof_invoices\" & Range("A14").Value & ".xlsx"
    ActiveWorkbook.SaveAs NewFN, FileFormat:=xlExcel8
    ActiveWorkbook.Close
End Sub