Hello, we have a Canon TR4520 and the other day it decided to stop receiving and sending faxes to two numbers. Just these two numbers, it works with ever other number. If you call it the fax picks up but when it tries to send a fax to these numbers it says its busy and when those numbers try to fax it it's busy. We have reset it. We thought maybe the numbers are blocked but when we printed the rejected numbers it says no numbers are on the rejected list.
Please take one of the fax numbers that is not working and attempt to call it using a regular phone, like your cell phone.
Do you hear a fax tone?
Do you hear a busy signal?