This issue was discussed before but I have slightly different solution for it.
You can open your aria 2 looking for some youtube videos. I watched this one
:united_states:/:united_kingdom: Repair your FitBit Aria scale yourself! (youtube.com)
After having access to the open Aria 2, I applied wd40 in all four pressure sensors that are locate in every corner of the base.
After that, my Aria 2 started worked fine again.
