custom tree structure not importing into mcreator

I am trying to make a custom tree by using the structure feature in the 1.18.2 version of mcreator. i built the tree in a minecraft forge 1.18.2 superflat world with the mod i was working on installed. i copied it with structure blocks and pasted it with another structure block in the same world. it worked so i went to import it into mcreator. i clicked import structure into minecraft and the structure didn't show up. what do i do to fix this?