SteamBot Cant send trade offer

public override void OnMessage (string message, EChatEntryType type)
{
    if (message.StartsWith("@") && IsAdmin) // interpret commands (from admins only for now)
    {
        string[] messargs = message.Split(' ');

        switch (messargs[0])
        {
            case ("@help"):
                SendChatMessage("@help - Displays this help message");
                SendChatMessage("@buy [key-amount] - Sends you a trade offer for purchasing a Mann Co. Supply Crate Key.");
                SendChatMessage("@sell [key-amount] - Sends you a trade offer for selling a Mann Co. Supply Crate Key.");
                break;
            case ("@buy"): // they wanna buy my keys!
                SendChatMessage("ALLOW ME TO PROCESS YOUR ORDER.");
                RefreshKeyRefVals();

                if (messargs.Length < 2)
                {
                    SendChatMessage("SORRY! PLEASE SPECIFY HOW MANY KEYS YOU WANT TO BUY.");
                    Log.Info("They ({0}) wants NULL key(s).", OtherSID.ConvertToUInt64());
                    break;
                }

                UInt16 keyAmount = 1;
                if (UInt16.TryParse(messargs[1], out keyAmount))
                {
                    if (keyAmount > NumOfKey)
                    {
                        SendChatMessage("SORRY! I DON'T HAVE THAT MANY KEYS.");
                        break;
                    }
                }
                else
                {
                    SendChatMessage("SORRY! I CAN'T GIVE YOU '{0}' KEYS.", messargs[1]);
                    break;
                }

                Log.Info("They ({0}) wants to buy {1} key(s) for {2}.", OtherSID.ConvertToUInt64(), keyAmount, Bot.SellKeysFor * keyAmount);
                SendChatMessage("YOU WILL GET {0} key(s) FOR {1}", keyAmount, Bot.SellKeysFor * keyAmount);

                List<long> contextId = new List<long>(); contextId.Add(1);
                TradeOffer offer = Bot.NewTradeOffer(OtherSID);

                UInt16 keysAdded = 0;
                Bot.GetInventory();
                foreach (var a in Bot.MyInventory.GetItemsByDefindex(5021))
                {
                    offer.Items.AddMyItem(440, 1, (long) a.Id);
                    keysAdded++;
                    if (keysAdded == keyAmount)
                        break;
                }

                TF2Value metalAdded = TF2Value.Zero;
                GetOtherInventory();
                foreach (var a in OtherInventory.GetItemsByDefindex(5002)) // ref
                {
                    if (metalAdded + TF2Value.Refined <= Bot.SellKeysFor * keysAdded)
                    {
                        offer.Items.AddMyItem(440, 1, (long)a.Id);
                        metalAdded += TF2Value.Refined;
                    }
                    else
                        break;
                }
                foreach (var a in OtherInventory.GetItemsByDefindex(5001)) // reclm
                {
                    if (metalAdded + TF2Value.Reclaimed <= Bot.SellKeysFor * keysAdded)
                    {
                        offer.Items.AddMyItem(440, 1, (long)a.Id);
                        metalAdded += TF2Value.Reclaimed;
                    }
                    else
                        break;
                }
                foreach (var a in OtherInventory.GetItemsByDefindex(5000)) // scrap
                {
                    if (metalAdded + TF2Value.Scrap <= Bot.SellKeysFor * keysAdded)
                    {
                        offer.Items.AddMyItem(440, 1, (long)a.Id);
                        metalAdded += TF2Value.Scrap;
                    }
                    else
                        break;
                }

                if (metalAdded < Bot.SellKeysFor * keysAdded)
                {
                    SendChatMessage("SORRY! YOU DON'T HAVE ENOUGH PURE METAL.");
                    if (!IsAdmin)
                    {
                        offer = null;
                        break;
                    }
                    else
                        SendChatMessage("but who cares youre an admin");
                }

                SendChatMessage("PREPARING TO SEND TRADE OFFER.");
                string offerID = "";
                string myinfo = "IF THERE WAS AN ISSUE WITH YOUR TRADE, LET MY MANAGER KNOW: https://steamcommunity.com/profiles/76561198132899910";
                bool offersent = false;
                for (int i = 0; i < 20; i++) // keep trying until it succeeds (BUT IT NEVER DOES!)
                {
                    try { offersent = offer.Send(out offerID, myinfo); }
                    catch { }

                    if (offersent) break;
                }

                if (offersent)
                {
                    Log.Info("Sent trade to {0}. OfferID: {1}", OtherSID.ConvertToUInt64(), offerID);
                }
                else
                {
                    SendChatMessage("SORRY! I COULDN'T SEND THE TRADE OFFER. THIS IS PROBABLY A PROBLEM WITH STEAM, PLEASE TRY AGAIN LATER.");
                }

                break;
            case ("@sell"): // they wanna GET RID OF their keys!
                if (message == "@sell tf2key") { }
                break;
            default:
                SendChatMessage("UNKOWN COMMAND! PLEASE TYPE `@help` FOR A LIST OF COMMANDS");
                break;
        }
    }
    else
        SendChatMessage("SORRY, THIS BOT IS NOT CURRENTLY AVAILABLE FOR PUBLIC USE. SEE YOU SOON!");
}