Automation error/Library not registered in VBA New OneNote.Application

Question

Using OneNote 16 and I am trying to open Onenote Through VBA However getting an error - Automation error/Library not registered.

Microsoft Onenote 15.0 library has already been selected.

I am trying below which is not working and getting an error in the line onApp.OpenHierarchy folderPath & fileName, ""

And the rest of the code below.

Sub ModifyOneNoteFilesInFolder()

    Dim folderPath As String
    Dim fileName As String
    Dim onApp As Object

    ' Specify the folder path where your OneNote files are located
    folderPath = "C:\Users\YourUser\Desktop\YourFolder\"

    ' Create OneNote application object
    Set onApp = CreateObject("OneNote.Application")

    ' Loop through all .one files in the folder
    fileName = Dir(folderPath & "*.one")

    Do While fileName <> ""

        ' Open the OneNote file
        onApp.OpenHierarchy folderPath & fileName, ""

        ' Add the text "Testing" to the current page
        onApp.Windows(1).ActivePage.Content.ExpandOutline
        onApp.Windows(1).ActivePage.Content.AppendLine "Testing"

        ' Save the modified OneNote file
        onApp.Windows(1).ActivePage.Save

        ' Close the OneNote file
        onApp.Windows(1).Close

        ' Get the next file in the folder
        fileName = Dir

    Loop

    ' Clean up
    Set onApp = Nothing

End Sub