EA is on the chart but not opening trades

A smiling face means the EA loaded. It does not mean the EA is receiving anything, and it does not mean it is permitted to trade. These are three separate conditions and they fail independently.

Error 4752: there are TWO permission switches, not one

If the Experts tab shows OrderSend error 4752 (ERR_TRADE_DISABLED), the signal arrived, the syntax parsed, and MetaTrader refused to place it. Nothing is wrong with your alert, your script or the bridge - the order was rejected on permissions alone. This is the single most common false alarm, because everything upstream looks healthy.

MetaTrader has two independent permission levels and BOTH must be on. People check the first, see it lit, and stop looking.

• •Terminal level - the Algo Trading button in the MT5 toolbar. It should be lit/green. Also check Tools > Options > Expert Advisors > Allow automated trading.
• •EA level - right-click the chart > Expert Advisors > Properties, then the Common tab (NOT Inputs) > tick Allow Algo Trading. This is the one that is usually missed, because the Inputs tab is where you configure everything else, so it is the tab already open.

If both switches are already on

• •Investor password - logging in with the read-only investor password disables trading at the account level and looks exactly like this. Re-login with the master password.
• •Market closed - gold has a daily break and a weekend gap. An order arriving in the gap is refused.

Read the Experts and Journal tabs

In the Toolbox at the bottom of MetaTrader, the Experts tab shows what the EA is doing and the Journal tab shows what the terminal did with it. Between them they will usually name the problem outright. People skip these two tabs and then guess for an hour.

Rejections that look like silence

• •Invalid volume - the size requested is below the broker's minimum, above its maximum, or not a valid step. Common when a percentage-based size rounds to something the broker will not accept.
• •Not enough money - the free margin will not support the position at the requested size.
• •Market closed - gold has a daily break and a weekend. A command arriving in the gap is refused.
• •Trade context busy - another operation was in flight. Usually transient.
• •AutoTrading disabled by client - the toolbar button, not the EA.

Check the account allows it

Some accounts - particularly funded and evaluation accounts - restrict automated trading, restrict certain instruments, or disallow trading around scheduled news. The EA will look perfectly healthy and simply have every order refused. Read the account's own rules before assuming a software fault.