Hi RiceKing,
Thank you for using the Support Forum. please make sure you are using the default for both the username and password. If you are still unable to access the machine you will need to have service to reset the machine. See this solution for an explanation. Please consider contacting your support centre for further assistance.
For some reason the ADMIN password on our WorkCentre 6400 doesn't work anymore. I've already tried the default 1111.
How to reset it?
Thanks
Rice