Why is this script not giving me the gun and giving me an error on line 10?

Problem:

• You called the function while setting the callback. This would not work as the function would get called without a request to process. This would make it so that "receiptInfo" would be nil.

Solution:

• Remove the "()" on line 31.

Explaining the Error:

The error: Attempt to index nil means you are trying to index something (properties, child, function, etc) that doesn't exist. In Lua (the coding language Roblox uses), things that don't exist are called nil.

Fixed ServerScript:

local MarketplaceService = game:GetService("MarketplaceService")
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local gun = ReplicatedStorage:WaitForChild("Handgun")
local players = game:GetService("Players")
local receiptInfo = ga

local productId = 986593881

local function proccessReceipt(receiptInfo)

    local player = players:GetPlayerByUserId(receiptInfo.PlayerId)
    if not player then
        --the player probably left the game
        --if they come back, the callback will be recalled
        return Enum.ProductPurchaseDecision.NotProcessedYet
    end

    if player then
        -- what do you want the dev product to do
        local char = game.Workspace:FindFirstChild(player.Name)
        local gunClone = gun:Clone()
        gunClone.Name = "Gun"
        gunClone.Parent = char
    end

    return Enum.ProductPurchaseDecision.PurchaseGranted

end

--set callback
MarketplaceService.ProcessReceipt = proccessReceipt