FaceTime not connecting!!!!!!!!!!!!!!!!!!!!

Basically when FaceTime rings on my devices (iPhone 5 & iMac 27 inch late 2012). I will answer on the iMac and it will say connecting however it will still continue to ring on the iPhone, after a little while it will fail to connect and I then have a missed call alert on both devices.

I thought maybe because I have it ringing on two devices it is confusing the system, so i proceed to turn the iPhone off. The other person will then ring again and the same issue still occurs. so to recap i will click answer and it will say it is connecting and then a while later it, I will receive a missed FaceTime call fromt the person.

I also try to call the other person and they encounter the same issue!

Can someone give me a solution please!!!!!