I have the following but it says Autofill method of range class failed. And then highlights the text below in red;

With Worksheets("M")
 .Range("A6").FormulaR1C1 = "=RC[20]"
    .Range("A6").AutoFill Destination:=Range("A6:A600"), Type:=xlFillDefault
        
    .Range("R6").AutoFill Destination:=Range("R6:R600"), Type:=xlFillDefault
        
    .Range("W6").FormulaR1C1 = _
        "=IFERROR(VLOOKUP(RC[-3],'In-Play Amelco Categorys'!R[-5]C[-15]:R[201]C[-14],2,0),"""")"
    .Range("W6").AutoFill Destination:=Range("W6:W600"), Type:=xlFillDefault
        
     .Range("AA6").FormulaR1C1 = _
        "=IFERROR(INDEX(R6C21:R2000C21,MATCH(RC[-1],R6C18:R2000C18,FALSE),1),"""")"
    .Range("AB6").FormulaR1C1 = _
        "=IFERROR(LOOKUP(2,1/(R6C18:R2000C18=RC[-2]),R6C21:R2000C21),"""")"
    .Range("AA6:AB6").AutoFill Destination:=Range("AA6:AB675"), Type:=xlFillDefault
End With