Hi,
This is weird since the default setting for add new ticket on client-side, the email always being sent to the client:
http://www.osticket.com/forums/showthread.php?t=2059(http://www.osticket.com/forums/showthread.php?t=2059)
Make sure that the email's client you entered when you add new ticket on staff-side is different with the staff's email to check the client should be receiving the email. Besides that, osTicket System will avoid the same email sent twice (ie, usually when we do test by entering the same client's email with staff's email).
Best regards,
Masino Sinaga