Can you receive any faxes. Run a Fax Test from the Tools menu. Is the problem with only one fax receipient? (Check the phone number and make sure they are set to receive. I have dealt with one fax receipient where the call-waiting service caught the fax call.)
Does the Fax see a dial tone? If there is no dial tone, use a single line phone (corded) to listen for a dial tone at that jack. If there is no dial tone, check the incoming service for a dial tone. (If you have no dial tone at all, contact your service provider.) Try a new phone cable (2-wire RJ-11) Try calling the number from another phone line with the single line
phone attached. If the phone doesn't ring with a new cable, check your wiring and then contact your provider. Is the signal analog or digital (the all-in-one is designed for digital)?
Go back through the fax settings and set it as directed in Step 2 here: http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01458259&tmp_task=solveCategory&lc=en&dlc=en&cc=us&lang=en&product=3643612
. You need the fax error reporting setting.
Disconnect any items that are plugged into the 2-Ext port.
Try reinitializing the unit. Unplug the power cord with the unit on. Make sure that the phone cord is fully seated in the 1-Line port. Then reconnect the power cord.
Try resetting the all-in-one, this may require 2 people. With the printer on, unplug the power cord and wait at least 20 seconds. Press and hold # and 3 while plugging in the power cord. Release the buttons after the unit starts up.
If none of these steps help the unit may need service.