You need settings to use an answering machine.
Select Settings on the home screen on the printer's control panel.
To select an item, use the 
buttons, and then press the OK button.
Select Fax Settings > Basic Settings.
Set Receive Mode to Auto.
Set the Rings to Answer setting of the printer to a higher number than the number of rings for the answering machine.
If Rings to Answer is set lower than the number of rings for the answering machine, the answering machine cannot receive voice calls to record voice messages. See the manuals that came with the answering machine for its settings.
The printer's Rings to Answer setting may not be displayed, depending on the region.