How to fix? ServerScriptService.Main:30: attempt to index nil with 'Name' - Client - LocalScript:2

This is the second time i have posted this. Someone please help. So the problem is, I have a pet store, when you walk over it a gui comes up very well there is a scrolling place there is a close button. But when you try to press the buy button and you have enough money It comes up with this error 'ServerScriptService.Main:30: attempt to index nil with 'Name' - Client - LocalScript:2' and does nothing.

LocalScript:2

script.Parent.MouseButton1Click:Connect(function()
	local result = game.ReplicatedStorage.RemoteFunctions.EquipPet:InvokeServer(script.Parent.Parent.Name)
end)

ServerScirptService Main:

game.Players.PlayerAdded:Connect(function(player)
	local leaderstats = Instance.new('Folder', player)
	leaderstats.Name = 'leaderstats'
	
	local Pets = Instance.new('Folder', player)
	Pets.Name = 'Pets'
	
	local coins = Instance.new('IntValue', leaderstats)
	coins.Name = 'Coins'
	coins.Value = 0
	
	player.CharacterAdded:Connect(function(char)
		local attachment = Instance.new('Attachment', char.HumanoidRootPart)
		attachment.Name = 'CharacterAt'
		attachment.Position = Vector3.new(3,3,0)
	end)
end)


game.ReplicatedStorage.Remotes.Add.OnServerEvent:Connect(function(player, ammount)
	local currency = 'Coins'
	local ammount = 1000
	player.leaderstats[currency].Value = player.leaderstats[currency].Value  + ammount
end)

game.ReplicatedStorage.RemoteFunctions.EquipPet.OnServerInvoke = function(player, pet)
	local currency = 'Coins'
	local MainPet = game.ServerStorage.Pets:FindFirstChild(pet)
	
	if not player.Pets:FindFirstChild(MainPet.Name) then
		if player.leaderstats[currency].Value >= MainPet.Price.Value then
			player.leaderstats[currency].Value = player.leaderstats[currency].Value - MainPet.Price.Value
			local clonedPet = MainPet:Clone()
			clonedPet.Parent = player.Character
			clonedPet:SetPrimaryPartCFrame(player.Character.Head.CFrame)
			
			local atPet = Instance.new('Attachment', clonedPet.PrimaryPart)
			
			local ap = Instance.new('AlignPosition')
			ap.Parent = clonedPet
			ap.RigidityEnabled = true
			ap.Attachment0 = atPet
			ap.Attachment1 = player.Character.HumanoidRootPart.CharacterAt
			
			return 'Bought'
		else
			return 'Not enough coins'
		end
	else
		return 'Equip'
	end
end

This error means that Mainpet has no value (nil). You didn't send in an argument for the pet during :InvokeServer(). Because of this, Mainpet also has a value of nil. You need to send in a pet argument when doing InvokeServer