Problem with exporting illustrator file

Hi! I used the pen tool and pathfinder to cut shapes when I was creating my project in illustrator. But when I finished my project and saved it on my computer, I discovered the problem. Every line created with the pen tool and pathfinder is now visible. I tried to change the export settings, but nothing happened. This project looks fine in illustrator. What's wrong and what should I do? It's my first time in illustrator