Troubleshooting
Use this page to diagnose common problems with strategy building, data, backtests, exports, and optimization runs.
Start here
- Read the error or status shown in the current page.
- Confirm that the strategy has generated code and that the selected data covers the requested frequency and dates.
- Refresh the relevant page and reopen the strategy, report, or optimization.
- If the same error persists, record the strategy or run ID and the exact message before contacting support.
Chat and code
Lona’s response does not match the strategy
State the entry and exit rules, indicators, parameter values, position behavior, and risk constraints explicitly. Review Identified rules in the backtest panel and continue the chat with corrections before building code.
The model selector changes the chat model, not the backtesting engine. See AI models for the current choices.
The strategy cannot be built
Make sure the conversation contains enough information for Lona to identify the trading rules. Code generation should start automatically when the rules are clear. If the rules appear without code, use Build Strategy to backtest as a fallback. If generation still does not start, refresh the chat and try again.
Generated code is incorrect or does not run
Compare the source with Identified rules in the canvas. If the logic is wrong, clarify the requirement in chat and build the strategy again. If execution fails, use the error details, check edited code for syntax or parameter issues, and try a smaller date range or simpler data selection to isolate the problem.
Backtest configuration and results
No suitable frequency is available
The data selector computes the frequencies common to every selected symbol. Select symbols with a shared frequency, or remove a symbol. Global data supports 1d, 4h, 1h, 15m, and 5m; free/basic global-data access is limited to 1d.
The requested date range is rejected
Selected symbols must all cover the requested start and end dates. Shorten the range to the displayed overlap, choose another symbol, or select a different frequency.
The backtest has no trades
Check that the entry conditions can occur in the selected period, that indicator lookback periods have enough bars, and that the selected parameters are reasonable. Review the data timestamps and price columns, then run a baseline with a wider range or a different symbol.
The result looks unrealistic
Check the uploaded data for gaps, duplicate rows, incorrect units, timezone errors, and bad OHLC values. Review initial cash, commission, leverage, buy-on-close behavior, and the generated code. A backtest result is historical simulation output, not a guarantee of live performance.
CSV upload
The file is rejected
Upload a UTF-8 CSV text file no larger than 30 MB. Binary files, UTF-16 files, empty files, and non-CSV spreadsheet files are not accepted by the browser upload flow.
Required columns cannot be mapped
Map Timestamp and Close. Map Open, High, Low, and Volume when those columns exist. Check the preview and confirm that the header row was detected correctly. The upload flow is for OHLCV data; the Custom Data label refers to this user-upload path.
Dates or prices parse incorrectly
Use consistent timestamp values, preferably ISO-style dates or UTC timestamps. Check that price columns are numeric, that the selected frequency matches the bars, and that the source’s timezone and units are known. Lona shows processed coverage and validation warnings, but you remain responsible for the quality of an uploaded source.
Optimization runs
The optimization cannot be submitted
Confirm that:
- at least one numeric parameter grid is configured;
- no more than two parameters are being swept;
- every grid has a valid minimum, maximum, and positive step;
- the selected data has a common frequency and overlapping date range; and
- the objective has a target metric and maximize/minimize direction.
The free/basic plan also has a limit of two lifetime free optimizations and a maximum of 400 iterations per optimization. Paid tiers do not use the basic 400-iteration cap, but paid runs consume optimization credits.
The optimization is still running
The detail page streams status updates and displays completed versus total iterations and an ETA. Refreshing the page reloads the optimization and results. The terminal states are Completed, Failed, and Cancelled.
Cancel does not finish immediately
Select Cancel and confirm the cancellation. The request is asynchronous; keep the detail page open or refresh it until the status becomes Cancelled. Results already written before cancellation may remain available.
Results or charts are empty
Wait for result updates, then refresh the detail page. The Results table is always available when results exist. A 2D chart appears only when one parameter varies; a 3D surface appears only when two parameters vary. Fixed parameters do not create chart axes.
An optimization fails
Read the error banner and check the strategy, data coverage, simulation settings, and parameter values. Reduce the date range, use fewer symbols, or test the strategy with an ordinary backtest first. If a worker or data error repeats, provide the optimization ID and error message to support.
MT5 export
Export is unavailable
MT5 export is available on a strategy detail page for Pro users and requires strategy code.
The export failed
Generation failures mean the strategy could not be translated to MQL5. Compilation failures include compiler diagnostics. Confirm the strategy backtests successfully, then retry. A completed export provides an .mq5 source file and .ex5 binary in a ZIP; its download URL is temporary and can be requested again from Export History.