iOS Question xui.Msgbox2Async not called in app at start

Dim T As String = "See Medicolegal disclaimer?"
    Dim Title As String = "www.makindo.co.uk"
    Dim sf As Object = xui.Msgbox2Async(T, Title, "Yes", "Cancel", "No", Null)
   
    Wait For (sf) Msgbox_Result (Result As Int)


   
    ' Handle the result
    If Result = xui.DialogResponse_Cancel Then
        Log("User cancelled the dialog")
        updated = True
   
        Return
    End If

    If Result = xui.DialogResponse_Negative Then
        Log("User chose No")
        updated = True
       
        Return
    End If

    If Result = xui.DialogResponse_Positive Then
        Log("User chose Yes")
        ' Continue with the process
    End If