To confirm, the Dangerous Things KBR1 IS working but the Vivokey app on your phone is not? Shortly after install there will be swelling and getting good reads is hard. Your model of phone may also have less than ideal NFC performance and/or a weird antenna placement. Check this thread to see if there’s any helpful info on your specific phone. Remember that placement and orientation are important. You can also try to get the xLED to light with your phone to ensure you’re using a good location and orientation.