The BP calibration process requires to measure your blood pressure twice. When the difference of systolic blood pressure between two measurements are too big, the BP calibration will fail. Please wait for a few minutes and then try again.
Pick up your Performance Monitor and select <Body Check> on the first menu screen; follow the on screen instructions and hold device as shown below. Note do not forget to place one of the fingers on your RIGHT hand on the silver sensor on the back of device.