"The port was disconnected by the user."

This error message is usually pretty self explanitory.

Usually this means that the user, or users computer disconnected from the remote computer. In many cases the user clicks on the disconnect button accidently.

There is also the chance that your computer disconnected you for a reason, if you don't know why your computer disconnected you, make sure that you don't have any other fax or modem programs running, but in most cases the user clicked the 'disconnect' button.