Call Xerox, supply the Serial number and the current meter read (Total impressions) and they can/would/should supply a pin code and can explain how to enter it on/at the device.
By default, all near Xerox devices are user = admin pass = 1111, so try that first after a reboot.
I have a WorkCentre 3315 that's admin password was not documented by the previous IT personel, What is the procedure for reseting it?