Problem with list leaderboard from lua runtime function

I’m using this code:

local records, owner_records, next_cursor, prev_cursor = nk.leaderboard_records_list(id, owners, limit)

As id I put the id of a leaderboard containing a lot of rows. After I return the length of “records” (is a table) and I obtain 0. This is strange, because if i try to get the same leaderboard from client (with Unity library), i get 100 rows (i set the limit to 100).