I don't understand pallets

So I’m new to art, got aseprite to edit some sprites for a game of sorts(more of a chat room).
And when I want to get a sample of a color from another picture it just goes to some color from the color palette of the original. Now I tried adding the color palette from the sample picture to the main one and it still doesn’t work. I’m sorry that this is a really stupid question, but I just can’t figure it out on my own.

Figured it out, color mode was set to Indexed.