local function LoadLeaderboardSave(player)
if player.userId <= 0 then return end --error here
player:WaitForChild("leaderstats")
wait()
local leaderboardStats = leaderboardData:GetAsync(player.userId)
for i, stat in pairs(leaderboardStats) do
local currentStat = player.leaderstats:FindFirstChild(stat[1])
if not currentStat then return end
currentStat.Value = stat[2]
end
Print("Loaded "..player.Name.."'s leaderstat data")
end
this is the error
ServerScriptService.Leaderboard:167: attempt to index nil with 'userId'

2 comments
provide us with more information about the script, the error at line 167
show the part where you use LoadLeaderboardSave() i think the player param is wrong