INVALID SYS passwrod

Hi all,

when I set the environment and log in as sys, it's wokring fine; however, when I log in the database as SYS and using the connect string, Oracle tells me it's INVALID password.

ON SQl net, I already set:

#NAMES.DEFAULT_DOMAIN = qdev.net

#SQLNET.AUTHENTICATION_SERVICES= (NTS).

on the init.ora, I have
remote_login_passwordfile=EXCLUSIVE (which is the samething with other instances on the same server, and I was able to log in the isntances instance fine using the connect string)

what am I missing here????

thanks,