DIAGNOSIS This is a loss of LiDAR positioning. The robot's laser distance sensor (LDS) on top is dirty or obstructed.
FIX Power off the robot. Clean the transparent plastic dome covering the spinning LDS module with a microfiber cloth. Remove any hair or string wrapped around the base of the dome. Also, ensure the charging base is in an open area, not tucked in a dark corner.
IF THAT DIDN'T WORK The floor plan may be too uniform (e.g., all one color, no furniture). Add a distinct rug or a temporary object in the room to give the robot visual landmarks.
HEADS UP Never place the base between two tall objects like chair legs. It needs a clear line of sight for the robot to dock and map correctly.