Internal error on command:"MEASURE_LINEAR_VIBRATIONS_RANGE"

I am trying the Linear Movement Vibrations Analysis. For this I have added to printer.cfg:

[linear_movement_vibrations]
accel_chip: adxl345 toolboard
x_min: 5
x_max: 295
y_min: 5
y_max: 295
output_directory: /home/pi/klipper_config/linear_vibrations/

Wen I run MEASURE_LINEAR_VIBRATIONS_RANGE AXIS=x VMIN=100 VMAX=500 STEP=20 D_IDLER=13 (what's the correct oidler value) it goes though the tests, generated the graphics and them immediately runs into the error in the title.

MEASURE_LINEAR_VIBRATIONS VELOCITY=200 AXIS=x works without any issues.