We recommend that you to make sure that the trainer or bike has the latest firmware version available from the manufacturer's site, otherwise the simulator won't be able to detect or control the trainer's resistance properly.
Also check that the trainer or bike is not paired via Bluetooth to any other device or app, because in that case it would be invisible for the rest of computers or tablets. Bluetooth allows one only connection at a time.
Please check this out in case of Android devices: go to Settings -> Applications -> Bkool Cycling -> Permissions and enable the location permission.
Then open the BKOOL simulator and enter the pairing menu. In the main screen, click on Forget my devices and unlink them.
Then close the simulator program entirely. This way we'll make the pairing again, from the scratch. Open the BKOOL simulator and try the pairing again, the ANT + and Bluetooth icons should be highlighted at the top right corner. Otherwise there could be a problem recognising the ANT+ USB stick or the Bluetooth antenna might not be working. Select the trainer or bike again and exit the Pairing screen.