Hi @valpop
If you've verified that your USB devices are working when connected to USB ports on other devices then try resetting the Chromebook hardware and check if that resolves the problem.
Turn of the laptop if it is on and then wait 30 seconds.
Then ''press and hold'' the Refresh and Power keys (both together) and release the Refresh key when the laptop starts up.
Boot up the laptop and check if the USB port now works.