That's what I thought. Ran across this before. How I diagnosed it was to send a test fax to a known "good" fax machine, from my machine. That way I knew the connection was OK. In one case, the fax machine settings had to be changed (I found them in the manual for the machine). However, I did have one fax that wouldn't go through for one of our customers. Even though I was able to send a fax successfully to hundreds of other customers. So many times the fax is dependent upon the receiving end. See if that helps.