Position Sizer errors: the MT5 fix guide.

1. Enable algo trading (and the indicator’s permission)

Fixes cause 1. A Position Sizer is an indicator that sends orders programmatically: the terminal blocks that unless you allow it twice.

• Turn ON the “Algo Trading” button in the MT5 toolbar (it turns green).
• In the indicator’s settings, under Common, make sure “Allow algo trading” is checked for the Position Sizer itself.
• Click the panel button again and watch the Journal: a request appearing there means the block is gone.

2. Respect the broker’s lot rules

Fixes cause 2. Open the symbol spec (right-click the symbol > Specification) and copy the three numbers that matter: volume min, volume max and volume step.

• Set the panel’s size inputs so the result never goes below the minimum or off the step (on indices with step 0.1, a 0.01-granular size will bounce).
• Prefer the fixed lot mode while you validate, then switch back to risk-based sizing.
• Sanity-check any manual size first in the lot size calculator: it shows the volume aligned to the step.

3. Give the math a tick value (or size it elsewhere)

Fixes cause 3, the 0.00 lots. If the terminal exposes no tick value for the symbol in your account currency, no risk-based sizing can converge — not the panel’s, not anyone’s.

• Check the symbol’s Specification: if tick value is zero or empty, use fixed lots for that symbol.
• Trade the broker’s exact symbol (with suffix). Suffixed clones sometimes lack the data the bare name has.
• We saw this live with an index CFD on a JPY account: the right size existed, but only with the symbol’s own quote conversion. If sizing must not guess, it must fail closed with a reason instead of sending 0.00 or a wrong lot.

4. Fix invalid stops (10016)

Fixes cause 4. The broker enforces a minimum distance between price and stops; the panel cannot know your intent, only the spec.

• Read trade stops level in the Specification and keep SL/TP at least that many points away.
• On ECN accounts, send the order without stops and modify right after the fill if your panel supports it.
• Right after news, stop levels widen temporarily: retrying minutes later often just works.

5. Fix not enough money (10019)

Fixes cause 5. The size was mathematically right for your risk but the margin was not there.

• Halve the risk input and retry: if the order passes, it was margin, not the panel.
• Check the symbol’s margin rate and your account leverage in the Specification.
• On prop accounts, remember drawdown limits effectively cap the risk you should be taking per trade anyway.

6. Treat demo and live as different brokers

Fixes cause 6. Demo servers are generous with specs; live servers are not. Re-do fixes 2-4 against the live symbol spec before blaming the tool.

• Open the Specification on BOTH servers and compare volume step, stop level and tick value.
• Adjust the panel inputs to the live numbers.
• Run your first live trades at minimum size to validate the full path.

The panel sizes YOUR click. It does not size your strategy.

A Position Sizer is a manual helper: it waits for you. If your signals come from TradingView, someone still has to be at the terminal, read the alert, and click the right size at the right moment — and every cause above still applies to each manual order.

The automated path: sizing on every signal

A bridge like SignalForge receives each TradingView alert, calculates the size from your risk settings (fixed or percent-based), aligns it to the symbol’s volume rules and sends the order — and when the broker’s symbol data is unusable, it rejects with a logged reason instead of guessing a lot. That is the same fail-closed behavior we recommend for any sizing engine.