Ask the administrator of the machine or your dealer or service representative.
A user has to specify the System Manager ID and the PIN. If you have not changed the settings, check the default settings.
Default settings,
Default settings of the System Manager ID and the PIN
MF746Cdw / MF745Cdw / MF543dw / MF449dw / MF448dw : 7654321 for each model
MF743Cdw / MF741Cdw / MF656Cdw / MF654Cdw / MF653Cdw / MF652Cw / MF644Cdw / MF642Cdw / MF641Cw / MF455dw / MF453dw / MF452dw / MF451dw / MF445dw : Not specified for any model