MQL4 ERR_INVALID_PRICE_PARAM
MQL4 error 4107 invalid price parameter maps to ERR_INVALID_PRICE_PARAM: invalid price parameter for trade function. A price passed to a trade function is structurally invalid for the symbol or operation. Capture GetLastError immediately after the failed call, correct the cause, and retry only when the condition can change.
Open the Coding Agent, then choose MQL4 from the language menu.
#property strict
#property script_show_inputs
input double Lots = 0.10;
input int Slippage = 3;
void OnStart()
{
if(!IsTradeAllowed())
{
Print("Trading is not currently allowed or the trade context is busy.");
return;
}
RefreshRates();
double price = NormalizeDouble(Ask, Digits);
ResetLastError();
int ticket = OrderSend(Symbol(), OP_BUY, Lots, price, Slippage,
0, 0, "diagnostic", 0, 0, clrNONE);
if(ticket >= 0)
{
Print("Order opened. Ticket ", ticket);
return;
}
int error_code = GetLastError();
Print("OrderSend failed. error=", error_code,
" symbol=", Symbol(), " lots=", DoubleToString(Lots, 2),
" ask=", DoubleToString(price, Digits));
}The official MQL4 runtime table names error 4107 ERR_INVALID_PRICE_PARAM and defines it as “invalid price parameter for trade function.” A price passed to a trade function is structurally invalid for the symbol or operation.
The error number is evidence about one failed call, not a diagnosis of the whole EA. Read the API sentinel first, then call GetLastError immediately because that function returns the current _LastError value and resets it.
Start with the inputs and external state that existed at the failure point. A later log entry or a successful call can overwrite the useful context.
Recalculate all price fields from current symbol data. Repeating the same invalid parameter will not make it valid.
Keep the original trading and risk rules intact. A workaround that widens stops, increases volume, changes an account setting, or ignores a failed return value can hide the symptom while changing the system.
| Check | Action |
|---|---|
| The price is zero, negative, or not available for the symbol | Reject zero and non-finite prices before the trade call. |
| Digits or tick-size normalization is wrong | Normalize with properties from the exact order symbol. |
| Stop, limit, or pending price is on an invalid side of the market | Validate price direction for the selected order type. |
| A multi-symbol EA uses the chart symbol Point or Digits | Do not reuse chart-symbol price properties in a multi-symbol request. |
The script creates a normalized current-symbol Ask and records it on failure. Multi-symbol code needs symbol-specific Bid, Ask, Point, and Digits values.
The example improves validation and logging. It does not prove the operation will be accepted by a broker or behave safely in live trading.
#property strict
#property script_show_inputs
input double Lots = 0.10;
input int Slippage = 3;
void OnStart()
{
if(!IsTradeAllowed())
{
Print("Trading is not currently allowed or the trade context is busy.");
return;
}
RefreshRates();
double price = NormalizeDouble(Ask, Digits);
ResetLastError();
int ticket = OrderSend(Symbol(), OP_BUY, Lots, price, Slippage,
0, 0, "diagnostic", 0, 0, clrNONE);
if(ticket >= 0)
{
Print("Order opened. Ticket ", ticket);
return;
}
int error_code = GetLastError();
Print("OrderSend failed. error=", error_code,
" symbol=", Symbol(), " lots=", DoubleToString(Lots, 2),
" ask=", DoubleToString(price, Digits));
}Pineify can generate or revise one self-contained .mq4 file with MQL4-specific reference context. Its independent static checker returns MetaEditor diagnostics so you can repair source issues before testing in your own MT4 environment.
Open MQL4 Coding AgentStatic diagnostics do not prove runtime behavior, backtest results, broker compatibility, or live-trading safety.
Check the API return value before interpreting an error number from the log.
Call GetLastError immediately and record error 4107, symbol, prices, volume, ticket, and terminal state relevant to the operation.
Reject zero and non-finite prices before the trade call.
Compile the revised source, then test with the same MT4 build, broker, symbol, account permissions, and market state.
ERR_INVALID_PRICE_PARAM means invalid price parameter for trade function. The code should still identify which API returned failure and log the inputs used for that call.
The price is zero, negative, or not available for the symbol Digits or tick-size normalization is wrong Stop, limit, or pending price is on an invalid side of the market A multi-symbol EA uses the chart symbol Point or Digits
Recalculate all price fields from current symbol data. Repeating the same invalid parameter will not make it valid.
It reports the current _LastError value and resets it. Other operations can change the error state, so a delayed read may describe the wrong call.
Pineify can revise a self-contained .mq4 file, add validation and error logging, and return static MetaEditor diagnostics. It cannot prove broker acceptance, account permissions, market availability, or live execution.
Last verified against the linked official references on . Compile and test the final source in the MetaTrader 4 build, broker, symbol, and account environment you plan to use.
Define the requirement, inspect the generated source, repair diagnostics, and test the behavior in your own MT4 environment.
Open Coding Agent