symbol_not_found

The terminal doesn't know this symbol.

HTTP 404. Nothing reached the broker.

Likely cause: A typo, or the broker names it differently (suffixes such as .m or -ECN).

What to do: List symbols and use the broker’s exact name.

Retry: No. The same request gets the same answer; change something first.

Listed under Market data and platform support in Errors. Send the error’s requestId to support and we can find the request.