Cut extrude error

Hi all, i have tried importing and mated the outter track of the escalator as shown in the picture. However, when i reopened this file, the component was rendered lightweight, so i had to edit my sketch as it said "the sketch has dangling entities with other relations that no longer exist, edit the sketch and restore the original state". I followed, edited my sketch and enclosed the sketch with that blue rectangle, which is my desired cut. However, new problem emerges and i do not quite understand what this error implies. Please help! Thank you.