This means that your Brother machine experienced a communications error when sending or receiving a FAX. This is generally caused by either interference on the line, phone line connection or another device on the line.
Try resending the documents and see if the message no longer appears.
If the message still appears, there may be a problem with the way the Brother machine is connected or you may have a bad telephone line. Disconnect any other equipment on the telephone line, i.e. answering machine, modem, extra telephones, switching devices, adapters, etc. Make sure the telephone line is connected directly from the jack (socket) on the Brother machine labeled "Line" to the telephone wall jack (socket).
Try resending again. If the transmission is successful, the problem was created by the connection of the Brother machine and the other devices on the line. Reconnect the other pieces of equipment one at a time to see which is causing the problem. If the error continues to appear on the report, try connecting the Brother machine to a different telephone line or have the line checked by the telephone company.
To protect your investment against power surges and lighting, Brother strongly recommends that you connect your machine to a surge protector. In particular we suggest that you use a surge protector that is compatible with both standard AC power cords and telephone line cords. Surge protectors equipped with telephone jacks (sockets) will assist in insulating your machine from any power surge that might travel through a telephone line.