Errors

Errors come back in two places:

1. In the HTTP response, when the request itself is wrong (bad field, expired token, not found).
2. On the WebSocket, when the trading engine rejects an order or change after accepting the request (not enough margin, SL too close, market closed). See Orders are confirmed asynchronously.

A bot has to handle both.

REST errors

Same envelope as success, with success: false:

{
  "success": false,
  "code": 400,
  "data": null,
  "error": "Bad request",
  "message": "volume is greater than position volume"
}

error is a generic label; message is the reason — log it.

Status	Meaning	What to do
400	Bad request — a field is missing or invalid.	Fix the request; don't retry as is.
401	Missing, expired or invalid token.	Refresh the token and retry once.
403	Your scope can't do this (unauthorized to access this resource).	e.g. an API_Trader token calling reports, or an Investor session trading.
404	The order, position or symbol doesn't exist (or isn't yours).	Re-read state.
429	Too many auth calls from your IP.	Back off with jitter.
500	Server error.	Retry later with backoff; reconcile before resending an order.
503	A dependent service is unavailable.	Retry later.

WebSocket errors

Error frames look like this:

{
  "type": "bad_request",
  "session_id": "f6a1c2d3-…",
  "payload": { "message": "not enough free margin — this order needs 1082.34", "reason": "order_create" }
}

• type is bad_request, forbidden, not_found, unauthorized or internal_server_error.
• payload.reason is the action that failed (order_create, position_update, position_close, …) — use it to settle your in-flight request.
• A rejected order may instead arrive as order_rejected, with the Order and its rejection_msg.

Trading errors you'll see

When placing an order

Message (abridged)	Cause
couldn't create order, the market is closed for EURUSD	Outside the symbol's trading hours.
lot size 0.001 is out of range — allowed 0.01 to 50.00	volume outside min_value–max_value.
not enough free margin — this order needs …	Not enough free margin for this size.
you've reached the maximum number of open orders and positions (N)	Your broker's cap on open orders + positions.
market order is not allowed / limit order is not allowed / stop order is not allowed	That order kind isn't enabled for the symbol (see its orders field).
take profit is not allowed / stop loss is not allowed	SL/TP not enabled for the symbol.
this order type is not allowed for EURUSD	The symbol is buy-only, sell-only, close-only or disabled (trade_level).
buy limit price 1.09 must be less than or equal 1.08234	Pending price on the wrong side of the market.
stop loss price … must be less than or equal … / take profit price … must be greater than or equal …	SL/TP too close or on the wrong side — see the rules.
expiration time should be at least 5 minutes from now	expiry_at too soon.
invalid field type / invalid field side	Bad type, side, or expiration_policy value.

When modifying or closing

Message	Cause
you can't update market order	Only pending orders can be modified.
you can't update the order at this point	The order isn't pending anymore (filled, cancelled…).
position is not open	Already closed or closing.
volume is greater than position volume	Close volume larger than the position.
invalid close amount 0.00 — it must be between 0 and the position volume	Close sent without volume.
no live price available right now…	No recent tick for the symbol. Retry shortly.
trading is currently disabled for this symbol	Broker disabled the symbol.

Account-level

Message	Cause
unauthorized to access this resource (REST 403) / read-only (investor) session cannot place, modify or close trades (WebSocket forbidden)	An Investor (read-only) session tried to trade.
this trial account has expired	Demo trial ended.
account #N takes trades only from the MT4 mirror	The account is mirrored from MT4 and can't be traded directly.