Many laptops do not have a line-in only mic-in. A very few have a “magic” mic-in that can sense the signal level and adappt itself to line-level (which is around a 1,000 time greater signal).
If yours is not one of those then you are probably a candidate for one of the external soundcards that we know work well with Audacity - see this sticky thread: https://forum.audacityteam.org/t/sound-card-reviews/8375/1
WC