Your TradingView alert fired, PineConnector received the signal, and then MetaTrader 5 returned error 4756 instead of opening the trade. It is one of the most common error codes in automated MT5 trading, and the exact phrase it carries in your log determines the fix.
This guide explains what 4756 means, how to find the exact reason in your log, and how to clear it, including a PineConnector setting that resolves the filling-mode case.
What Error 4756 Actually Means
In MetaTrader 5, error 4756 is ERR_TRADE_SEND_FAILED. It means MT5 tried to send your order to the broker and the broker rejected it, so the order never reached the market.
The key thing to understand is that 4756 is an outer error, not the real reason. It is a wrapper that says the request failed, while the actual cause sits one line away in your log. So the first move is never to change your strategy. It is to read the log.
Step 1: Find the Real Reason in the Log
Open the Toolbox at the bottom of MT5 with Ctrl+T, then check the Journal and Experts tabs. The Experts tab shows what the PineConnector EA tried to do, and the Journal tab shows how the terminal and broker responded. The 4756 line sits in one of these, usually next to the symbol and the time your signal arrived. On PineConnector Edge, you read the same two logs from Portal → Edge instead, without opening MT5 or a remote desktop.
Read the few words right after the 4756 code. That phrase is the real problem, and it is almost always one of a short list: unsupported filling mode, no prices, invalid volume, invalid stops, invalid request, or a symbol issue. A line ending in "unsupported filling mode" points straight at the fix below, while "invalid volume" points at your lot size instead.
Once you know which phrase you are dealing with, match it to the right section below. Do not guess at a fix, and do not resend the same signal repeatedly while the cause is still uncertain; read the exact wording first.
Unsupported Filling Mode
Every broker accepts orders in a specific filling mode, which is the rule for what happens when an order cannot be filled in full at the requested price. There are three:
- Fill or Kill executes the whole order at once or cancels it entirely.
- Immediate or Cancel fills as much as it can right away and cancels the rest.
- Return keeps the unfilled part of the order live.
Brokers support different modes depending on how they route orders. Market execution accounts, common with ECN and STP brokers, usually expect Fill or Kill or Immediate or Cancel, while instant execution accounts behave differently. If your EA sends a mode your broker does not accept, the broker rejects the order and you get 4756 with "unsupported filling mode" in the log.
On a self-hosted terminal, older PineConnector EA versions offer a Broker Set option for this. Open the EA settings with F7. If your EA version has this setting, switch the Broker Set to Broker Set B, which uses a filling mode most brokers accept. Confirm your EA version supports this setting before changing it; PineConnector's error guide notes this option is on older EA builds specifically. Once you've made the change, send a fresh test signal to confirm it cleared the error, rather than resending the original one repeatedly. If Broker Set B does not clear it, PineConnector's error guide covers the other Broker Sets, since the right one depends on your broker's execution model.
On PineConnector Edge: Broker Set is in Portal → Edge → EA Settings, under Miscellaneous, and the tab advises changing it only when Support asks. If you hit this specific cause on Edge, contact PineConnector support first. Applying a change restarts the terminal, so signals pause for about a minute; confirm the tab says your saved settings are running before you resend. See the EA Settings guide.
The Other Things 4756 Can Mean
If the log shows something other than filling mode, use this table. Each reason maps to a fix in your PineConnector EA or your Symbol List. Read the full logged message before acting; these are the documented cases, not a ranked list of likelihood.
| Log Reason | How to Fix It |
|---|---|
| No Prices | The symbol is not active in your Symbol List. PineConnector's error guide says the EA typically enables it automatically after this error; check that it now shows a live quote before sending anything else, rather than resending against a symbol that still has no price. |
| Invalid Request or Trade Disabled | The symbol name does not match your Symbol List exactly. Names are case sensitive, so EURUSD and eurusd are not the same. |
| Invalid Expiration | On older EA versions, a Broker Set C option covers this; confirm your EA version supports it before changing it. On Edge, Broker Set is in EA Settings; change it only when Support asks (see the Edge note above). |
| Invalid Volume | The lot size breaks your broker's rules. Check the symbol's volume step and minimum in the Symbol List. |
| Invalid Stops | Your stop or target is too close to price. Use a pips or percentage target type in the EA, or widen the values. |
| Invalid Price | Your stop, target, or pending entry price is too close or invalid, such as a stop set beyond the take profit. Use pips based targets and larger values. |
| Requote Detected | Common on the MetaQuotes demo server, which has strict execution rules. Check the broker's returned detail, confirm whether any order was placed before retrying, and if it keeps happening, raise it with your broker or PineConnector support on that same demo setup rather than changing accounts to chase it away. |
How to Avoid 4756 in the First Place
A few setup habits stop 4756 from appearing at all:
- Set the correct Broker Set during setup, not after the first failed trade, if your self-hosted EA version has this option.
- Use pips or percentage target types rather than price, since TradingView and broker quotes differ. The PineConnector syntax guide covers the options.
- Confirm your symbol names with Symbol Mapping so every alert uses your broker's exact ticker.
- Test on a demo account before going live, so you catch a filling mode or symbol mismatch with no money at stake.
4756 always traces back to one specific line in your Experts and Journal logs (or Portal → Edge, if you're hosted); match that exact wording to the cases above rather than assuming which one applies. For the full list of MetaTrader codes and fixes, see our common MetaTrader errors guide or the PineConnector error guide.
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