"Unable to cast value to std::string" when looking for player?

Made a ModuleScript for presenting a player with a choice. My game worked fine until it got to running the following code:

local c = {
    'workspace',
    'terrian',
    'terrain',
    'spawnlocatoin',
    'lighting',
    'Great',
    'ServerScriptService'
}
Module:PromptChoice('KicksForTricks56','Services',c,'ServiceChoice')

But, currently, the script gives:

13:09:04.619 - Unable to cast value to std::string
13:09:04.630 - Stack Begin
13:09:04.664 - Script 'ServerScriptService.ChoiceScript', Line 12 - method PromptChoice
13:09:04.665 - Script 'ServerScriptService.Script', Line 12
13:09:04.667 - Stack End

What's wrong with the module script? For reference, here it is:

local http = game:GetService("HttpService")
local instructionMessages = {
    ["mobile"] = "press an option with your finger",
    ["gamepad"] = "press View, then nagivate to an option with the Left Stick and press A",
    ["computer"] = "click an option with your mouse/touchpad"
}
local wrapper = "(To make your choice, %s. Choose wisely!)"
local module = {}

function module.PromptChoice(player, caption, choices, identifier)
    local id = ""
    local playerA = game:GetService("Players"):WaitForChild(player)
    if playerA == nil or playerA.Parent == nil then
        error("Player does not exist")
        return false
    end
    if identifier == nil or identifier == '' then
        id = identifier
    else
        id = math.random(1,2000)
    end
    local json = http:JSONEncode(choices)
    local gui = script.ChoiceGui:Clone()
    local event = Instance.new("RemoteEvent")
    event.Name = player.."Choice"..id
    event.Parent = game.ReplicatedStorage
    gui.EventObject.Value = event
    gui.JSONChoices.Value = json
    gui.Caption.Text = caption
    gui.Instructions.Text = string.format(wrapper,instructionMessages[player.input.Value])

    gui.Parent = playerA.PlayerGui

    event.OnServerEvent:Connect(function(choice)
        local GoodToDo = false
        for i=1,#choices do
            if choices[i] == choice then
                GoodToDo = true
            end
        end
        if not GoodToDo then
            playerA:Kick("Don't know why you'd want to exploit on a game like this? Lol")
        end
        return choice
    end)
end

return module