为什么会出现错误“应用程序定义的错误或对象定义的错误”?

错误在哪里 application-defined or object defined error 来自哪里?它似乎来自我创造的公式。请帮忙。用VBA编写代码确实不应该这么难,但由于某些原因,它不起作用。

Sub get_levels()

    Dim Count As Integer
    Dim ticker As Variant
    Dim lastRow As Long
    Dim lastRowC As Long
    Dim rng As Range
    Dim current_input_position As Long
    Dim sheet As String
    Dim mula As String
    Dim updatedTicker As String

    Application.CutCopyMode = False
    Count = 0
    sheet = "Test_Sheet"

    current_input_position = 2

    lastRow = Cells(Rows.Count, "A").End(xlUp).row

    Label:

    Set rng = Range("A" & current_input_position & ":A" & lastRow)
    For Each ticker In rng.Cells

        lastRowC = Cells(Rows.Count, "C").End(xlUp).row
        updatedTicker = ticker & " A" & " Mtge"

        MsgBox updatedTicker 

        mula = "GCBDC 2018-1A A Mtge"

        Range("E2").formula = "=BDS(" & mula & ",""MTGE_CMO_GROUP_LIST"",""Headers=N"")"

    Next ticker


End Sub