Getting the following errors with Trello?

Below is the code I'm using, the actual "Trello Key" has been removed since it is a private key. The rest of the code is intact. Following the code is the exact "output" I received which contains the error which has stumped me. "07:23:47.557 - Key name is too long"

local Encode = LoadLibrary("RBXUtility").EncodeJSON
local DataStore = game:GetService("DataStoreService"):GetDataStore("Applications")
local DataToSend = {}

function Send()
    DataToSend["Name"] = game.StarterGui.ScreenGui.TextBox.Text

    local JSON = Encode(DataToSend)
    DataStore:UpdateAsync("https://api.trello.com/1/board/PRIVATETRELLOKEY",function(Old)
        local New = Old or {}
        table.insert(New,JSON)
        return New
    end)

    print("Sent")
end

script.Parent.MouseButton1Down:connect(Send)

Errors/Output: 07:23:47.556 - RbxUtility.EncodeJSON is deprecated, please use Game:GetService('HttpService'):JSONEncode() instead. 07:23:47.557 - Key name is too long 07:23:47.558 - Script 'Players.Player.PlayerGui.ScreenGui.TextButton.Trello', Line 9 07:23:47.558 - Stack End 07:23:47.559 - Disconnected event because of exception