Q: Subaru XV can read out messages but when we reply, it comes up "there is an error in sending message.  We cannot work out why.

My Subaru XV reads out messages received on my iphone without a problem, but when I hit reply, it comes up as "error, cannot send message".  We have checked everything in the car set up and everything appears correct.  We are wondering if we have missed changing something in the phone.  Can someone please help?