Landline phone says check tel line

To check where the issue may be, try this. Locate the MPOE (the box usually outside on your house that connects the in-house phone lines to the incoming line from AT&T) and disconnect the incoming wires from AT&T. Connect your phone unit to those wires and see what you get. If calls can go out and in, then it's your inside wiring, which unfortunately is going to be your responsibility. If there is still no dial tone, that's AT&T's problem and you'll have to get them out to check the line, either coming into your house or further down the street where the lines are bundled.