I have a 2005 sc430 using blue tooth my I Phone 8 was working fine for a long time now when I make a call my I phone screen asks me speaker, iphone,or use car and there is a check mark next to select car. If I select I phone then the radio does not mute but I can only receive and hear the call on the I phone if I leave the check mark set on the use the car settings the call goes through but radio only mutes when call is picked up and the mute button shows its muted on screen and I have to turn it off manually

The phone used to make the dial noise now with no dial noise it will connect and the the screen opens and person called answers but they cant hear me because the mute button is on in the screen I have to manual turn it off in order to converse . I have the phone set up as blue tooth hands free in the cars Bluetooth settings. it never did this before .

Would appreciate any help