The i20 (I20) error code appears when there is a water level or pressure sensor problem. Every time you run a cycle, the sensor may become affected by debris. Remove the two filters located below the bottom spray arm. There will be a small round hole on the tub’s left side. There is nothing to guarantee that the sensor will not get blocked.
The sensor may get spoiled, and you may need to replace it soon. The new kit will come with a filter cover, which should close the hole in the tub. Not unlikely, you will need professional help. Once you install the new sensor, the error will disappear.