Phone can't connect to car even though bluetooth is connected

In the last two week, I have started having a problem with my 2004 Prius and connecting phone calls. Bluetooth works and the phone connects. When I try to place a call from the car's audio system, it can't go through. If I initiate the call from my phone, it connects to the bluetooth perfectly and I can make the call. If anyone else has had this problem and found a solution, I would like to hear about it.

Thank you.