I had the same issues on my Direto. It is a Zwift problem (the Trainerroad app works perfectly over BT). Anyhow, for Zwift forget bluetooth. Plug your ANT+ dongle (I got this one - https://www.amazon.co.uk/gp/product/B00LIIMHP4 ) into your PC, give it a moment to install whatever drivers it needs.
You may need a usb extension cable, you may not, it depends on your setup. Usually line of sight will work fine over the length of a room.
Start Zwift up, give the crank a couple of turns. The lights will come on on the trainer. Enter the pairing menu, you’ll notice an ANT+ logo on the top left of the screen now, it should be pulsing. Your trainer should be called “Elite FE-C 9216”. Select it and away you go.
The next time you start Zwift after that, just give the pedals a spin and it should select it automatically, giving you a brief timer before moving onto the main screen.