Attempt to call a boolean value. Any fixes?

So I tried making a check for my shop so that I don't scam the players. So that if the event isn't running then they won't buy it. And It doesn't work. Here's the code. ServerScript:

local function checkEvent()
    if not EventRunning then
        return true
    else
        return false
    end
end
game.ReplicatedStorage.CheckEvent.OnServerInvoke = checkEvent()

LocalScript:

Frame.ShpBuy2.MouseButton1Click:Connect(function()
    local ChckEvnt = EventCheck:InvokeServer()
    print(ChckEvnt)
    if ChckEvnt then
        MarketService:PromptProductPurchase(plr, 1009546097)
    else
        print("No event is running!")
    end
end)