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MetaTrader error codes / MT4 trade server errors

MT4 error 129: Invalid price (ERR_INVALID_PRICE)

The price in the request is stale, on the wrong side, or not normalized. Nothing was executed; refresh rates and resend.

129ERR_INVALID_PRICE
After a fixSafe to retry?
NoCould it have executed?

What it means

You see this code in GetLastError() in MQL4, after a trade function fails on the server side.

The server didn't accept the open or close price. For a market order it must be the current Ask (buy) or Bid (sell), within the slippage you allow.

For pending orders the price must be on the correct side of the market.

Common causes

  • Ask or Bid used without RefreshRates() after a slow step.
  • A buy opened at Bid, or a sell at Ask.
  • A price with too many decimals.
  • A price calculated on another symbol's values.

How to fix it

  • Call RefreshRates() right before the send.
  • Normalize prices with NormalizeDouble(price, Digits).
  • For other symbols, use MarketInfo(sym, MODE_ASK) and MODE_BID.

Example in MQL4:

RefreshRates();
string sym = "GBPUSD";
int    dg  = (int)MarketInfo(sym, MODE_DIGITS);
double ask = NormalizeDouble(MarketInfo(sym, MODE_ASK), dg);
int ticket = OrderSend(sym, OP_BUY, 0.10, ask, 3, 0, 0, "", 4711);
if(ticket < 0) Print("error ", GetLastError());

Is it safe to retry?

Yes, with a fresh, normalized price.

Could the order have executed?

No. The server refused the price, so no order was opened, closed or changed.

How Tickwire handles it

Tickwire treats it like MT5 10015, and the MT4 code stays in the message. See trade results.

All MetaTrader error codes

One API for MT4 and MT5

Clear trade outcomes, idempotent orders and an audit log. Read the error reference or the quickstart.

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