VBA - What could interfere with a ClearContents function?

I am trying to use the following code to clear contents of a given cell depending on which input method the user chooses (Simplified vs calculator).

Private Sub Worksheet_Changeo(ByVal ChangedCell As Range)

    Application.EnableEvents = True
    
    If Not Intersect(ChangedCell, Me.Range("B31")) Is Nothing Then
    
        If Me.Range("B31").Value = "Calculator" Then
                Range("D30:E30").Select
                Selection.ClearContents
        End If
        
    End If
    
End Sub

The code seems to work just fine when using it in a fresh workbook, so it seems that something else in my current workbook might be interfering with it (I did directly save it in the relevant sheet module btw). Does anyone have any ideas on what might be stopping the code from erasing the contents of those two cells?

Thanks,

I tried writing a code which automatically erases old iput cell contents when switching input method, it seems to work on a new workbook but not my current one and I can't tell why. There is no error message or anything.

Solution

A Worksheet Change: Conditionally Clear Another Range

Since you haven't answered any of my clarification questions, I'm assuming you know that the target cell has to be manually changed which includes a change via a drop-down list but excludes formulas.
Here is how the suggestions in my comments could be applied. You already know the code must be copied to the correct sheet module.
To prevent retriggering this code when clearing the range, events need to be disabled. Therefore, I additionally implemented error handling so there's no way the events remain disabled.

Private Sub Worksheet_Change(ByVal Target As Range)
    
    Const CLEAR_RANGE_ADDRESS As String = "D30:E30"
    Const TARGET_CELL_ADDRESS As String = "B31"
    Const TARGET_VALUE As String = "Calculator"
    
    Dim tcell As Range: Set tcell = Me.Range(TARGET_CELL_ADDRESS)
    If Intersect(tcell, Target) Is Nothing Then Exit Sub
    
    Dim TargetString As String: TargetString = CStr(tcell.Value)
    If StrComp(TargetString, TARGET_VALUE, vbTextCompare) <> 0 Then Exit Sub
        
    On Error GoTo ClearError
        
    Application.EnableEvents = False
    
    Me.Range(CLEAR_RANGE_ADDRESS).ClearContents
    
ProcExit:
    Application.EnableEvents = True
    Exit Sub
ClearError:
    MsgBox "Run-time error [" & Err.Number & "]:" & vbLf & vbLf _
        & Err.Description, vbCritical
    Resume ProcExit
End Sub