The filter produced no results. Please select two overlapping paths

hello every one

i have been trying to make a module pattern based on this video:

https://www.youtube.com/watch?v=4JZARIfHg2I

, but when i want to use pathfinder intersect option it says "The filter produced no results. Please select two overlapping paths"

i also tried the solution people gave to the same problem to others, which was using expand or expand appearance, but my expand appearance is not avaible ( its gray) and when i press expand option, it just doesn't do anything, no window opens.

so i am in atrap -_-

my illustrator version is : Adobe Illustrator 2020