macOS and Bluetooth pairing timeout

So I have managed to get a r42 module working with an Arduino and sending data back and for.

However, I have a strange problem.

If I don’t connect to the port within approx 60 seconds the connection drops and the Bluetooth is unpaired.

I tried this on an Xbee too and it’s the same.

When I close the program ( eg cool term or BCnc ) the blue tooth is unpaired.

Has anyone got any suggestions? It’s a real pain having to re pair it every time.