Error in the SendUsingAccount and Organizer

I wrote a form with the code below:

    Set objOutlook = CreateObject("Outlook.Application")
    Set objAppt = objOutlook.CreateItem(olAppointmentItem)
Msgbox "test"
    With objAppt
        .Start = StartString
        .Organizer = "otheraccount"
        .SendUsingAccount = "otheraccount"    
        .duration = DurationString
        .Subject = [Mynote]
        .Body = BodyString
        .Location = ""
        .ReminderMinutesBeforeStart = "15"
        .ReminderSet = True
        .ResponseRequested = True

        .MeetingStatus = olMeeting
        Set Recip = .Recipients.Add(ScheduleTech.Column(0))
        Recip.Type = olRequired
        .Save
        .Send

    End With


It worked before.  I found that it is because the line of
        .Organizer = "otheraccount"
        .SendUsingAccount = "otheraccount"    
If I command it out, it works.  If not, it cannot even display the "test" message.
Could you tell me why?
Is it the upgrade for the office cause the issue?