ADXL372 with nrf52840 Registers configuration and data read problems

Hi,

I need to get max peak on all axes when an impact is detected. I have set the ADXL372 registers like this:

ADI_ADXL372_POWER_CTL = 0x00 --> start config
ADI_ADXL372_MEASURE = 0x2C
ADI_ADXL372_TIMING = 0x20
ADI_ADXL372_FIFO_SAMPLES = 0xFF
ADI_ADXL372_FIFO_CTL = 0x3A
ADI_ADXL372_X_THRESH_ACT_H = 0x00
ADI_ADXL372_X_THRESH_ACT_L = 0x23
ADI_ADXL372_Y_THRESH_ACT_H = 0x00
ADI_ADXL372_Y_THRESH_ACT_L = 0x21
ADI_ADXL372_Z_THRESH_ACT_H = 0x00
ADI_ADXL372_Z_THRESH_ACT_L = 0x21
ADI_ADXL372_X_THRESH_INACT_H = 0x00
ADI_ADXL372_X_THRESH_INACT_L = 0x23
ADI_ADXL372_Y_THRESH_INACT_H = 0x00
ADI_ADXL372_Y_THRESH_INACT_L = 0x21
ADI_ADXL372_Z_THRESH_INACT_H = 0x00
ADI_ADXL372_Z_THRESH_INACT_L = 0x21
ADI_ADXL372_TIME_ACT = 0X01
ADI_ADXL372_TIME_INACT_H  = 0X01
ADI_ADXL372_TIME_INACT_L = 0X01
ADI_ADXL372_INT1_MAP = 0x02
ADI_ADXL372_INT2_MAP = 0x02 (not used)
ADI_ADXL372_POWER_CTL = 0x02 --> end config
I haven't had interruptions with this config.
When i try to read the values on axes data registers (0x08 for example) I have some random values even if my device doesn't move.
I need help, thanks in advance for your time.
David