If the SMTP event sink on Exchange Server 2003 is not firing and not working as expected.
Please make sure that Event sink .vbs file is saved in ANSI Encoding not in UNICODE.
Because Event sink file in UNICODE will break script parser and hence Event Sink would not work.
How to save Event Sink file in ANSI Encoding?
· Open the Event Sink file using Notepad.
· File -> Save As
· Select -> Encoding as “ANSI”
· Save -> Click Yes for “File already exists, Do you want to replace it” prompt.
For sample SMTP event sink we can refer to the below mentioned article:
How to add a disclaimer to outgoing SMTP messages in Visual Basic script