DIAGNOSIS The phone line connection is faulty or the receiving fax machine is not answering. The beep is a handshake failure.
FIX Verify your phone cord is plugged firmly into the LINE port on the printer, not the EXT port. Listen for a dial tone through the printer's handset or by plugging a phone into the port. Ensure you're dialing the full number, including any outside line prefix like '9'.
IF THAT DIDN'T WORK Your internet/VOIP phone line may not support fax. Fax requires a traditional analog phone line. Test with a known good analog line.
HEADS UP Never plug the printer's phone cord into a digital wall jack from a cable modem. It can fry the printer's fax modem.