400 thrown when sub called from different sheet

I'm getting a very strange 400 error that I cannot explain.

I have two sheets

1. Reconciliation Reporting (Button pointing to a Sub "ThisWorkbook.ImportRawData"
2. Trading Day Processes, on which the import is actually happening also with a button pointing to "ThisWorkbook.ImportRawData"

When I click the button in Sheet Trading Day Processes everything works without a problem. When the button is clicked in Sheet Reconciliation Reporting then a 400 appears.

I have traced the error down. When I comment the part out everything works. I cannot find the reason for this 400 error, that the following part could cause.

tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeTop).LineStyle = xlContinuous
tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeTop).Weight = xlThick
tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeBottom).LineStyle = xlContinuous
tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeBottom).Weight = xlThick
tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeLeft).LineStyle = xlContinuous
tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeLeft).Weight = xlThick
tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeRight).LineStyle = xlContinuous
tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeRight).Weight = xlThick 

The ImportRawData sub (I have cut out the code that is not relevant for this error.

Sub ImportRawData()
' main function to importing from _data into Trading Day Processes
    Dim Workbook As Workbook
    Set Workbook = ThisWorkbook
    Set tradingDaySheet = Workbook.Worksheets("Trading Day Processes")

    ' variable needed for importing data
    Dim i As Integer
    Dim m As Integer
    Dim TDcurrentRow As Long
    Dim DAnumDataRows As Integer
    Dim MANnumDataRows As Integer
    Dim TDstartRow As Long
    Dim TDendRow As Integer
    Dim currentDatai As Integer
    ' variable to check if a row was importet successfully
    Dim importStatus As Boolean

    ' set the starting row in the Trading Day Processes Sheet
    TDstartRow = 11
    TDcurrentRow = TDstartRow
    ' get the amount of rows to import
    DAnumDataRows = CountDataRows
    ' set the end row
    TDendRow = TDstartRow + DAnumDataRows

    ' get the mount of rows for manual entries
    MANnumDataRows = CountManualRows



    ' check if the sheet is clean otherwise throw message
    If IsEmpty(tradingDaySheet.Range("C11").Value) = True Then

         ' Import Automatic processes
        For i = 1 To DAnumDataRows
            importStatus = ImportNextRow(i, TDcurrentRow, False)
            TDcurrentRow = TDcurrentRow + 1
        Next i

        ' Import Manual processes
        For m = 1 To MANnumDataRows

            importStatus = ImportNextRow(m, TDcurrentRow, True)
            TDcurrentRow = TDcurrentRow + 1
        Next m

        ' Create End of Day Balance
        CreateEndOfDayRow (TDcurrentRow)

        ' Create P&L Sheet
        'CreatePandLReporting (TDstartRow,TDcurrentRow)

    Else
        MsgBox "The _data sheet has not been cleared. Please clean the sheet first."
    End If
    MsgBox "Import Done. Happy reconciling"

End Sub

The Sub calls a function CreateEndOfDayRow(). I have cut out some code that is not relevant for this error (too long otherwise):

Function CreateEndOfDayRow(lastRow As Long)
' The function creates the end of day balance after all intraday processes have been imported
    Dim Workbook As Workbook
    Set Workbook = ThisWorkbook
    Set dataSheet = Workbook.Worksheets("_data")
    Set tradingDaySheet = Workbook.Worksheets("Trading Day Processes")
    Dim startRow As Integer
    Dim startRowIncStartBalance As Integer
    Dim rowDiff As Integer
    startRowIncStartBalance = 10
    startRow = 11

    ' calc difference between first and last row for automatic formulas
    rowDiff = lastRow - startRow
    rowDiffIncStartBalance = lastRow - startRowIncStartBalance

    tradingDaySheet.Cells(lastRow, 1).Value = "EOD Balance"

    tradingDaySheet.Cells(lastRow, 70).NumberFormat = FormattingModule.FormatHelper("Percentage")


    ===== CUT OUT CODE =======

      ====>The following lines seem to cause the error

     ' put fat boarder around balances
     tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeTop).LineStyle = xlContinuous
     tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeTop).Weight = xlThick
     tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeBottom).LineStyle = xlContinuous
     tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeBottom).Weight = xlThick
     tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeLeft).LineStyle = xlContinuous
     tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeLeft).Weight = xlThick
     tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeRight).LineStyle = xlContinuous
     tradingDaySheet.Range(Cells(lastRow, 1), Cells(lastRow, 70)).Borders(xlEdgeRight).Weight = xlThick

     SetLastRow (lastRow)

End Function

Maybe it has to do with the wrong use of Worksheets? As explained above when the Sub is called from within the same sheet everything works.