Verify senders are dialing the correct number and you are providing the sender with the correct fax number for your unit. If you have a second telephone number at your location or a cell phone, you can test the number yourself. Dial your fax number from the second telephone number or cell phone as if you are sending a fax. Then, pick up the external telephone handset and/or press the Hook, Hook/Hold, Speaker Phone or Tel/R key on your machine. Determine if what you are hearing on the phone you dialed from is consistent with what you are hearing on the FAX/MFC. For example, if you hear ringing on the dialing phone, but don't hear dial tone on the FAX/MFC, then there is a problem with the line or the number you are dialing. In this case, you will need to contact your local telephone company for assistance.