The number of rings for your answering machine is set to same or more than the printer's Rings to Answer setting.
Solutions
Set a number of rings for your answering machine lower than the printer's Rings to Answer.
To check the status of the fax settings, print a Fax Settings List. You can access the menu from the printer's control panel as described bellow.
Fax > (More) > Fax Report > Fax Settings List
Answering Machine Cannot Answer Voice Calls After Trying the Solutions Above
Solutions
If you cannot solve the problem, contact your printer administrator. For printer administrators, see the following section to troubleshoot fax problems.