Since the release of iOS 11, the WiFi and Bluetooth toggles in the Control Center don't actually turn off your device's Bluetooth and WiFi connections. This has been widely reported by the press (here and there for instance). This creates situations where the status of the Bluetooth (on or off) is different in your Settings and in your Control Center.
In order to connect your Rotator to the VR Maker app, both the Bluetooth and the device discovery function must be on.
Here is the recommended procedure to pair your Rotator with the VR Maker app:
1) Switch on your Rotator.
2) Turn on the Bluetooth in your Settings. You do NOT have to find the Rotator in the list of nearby devices that may show on your phone. Your phone will automatically connect to the Rotator.
3) Turn off and turn back on the Bluetooth in your Control Center.
4) Return to the VR Maker app to capture. Now your Rotator should be properly connected to your iPhone.