Unknown symbol '' was received. Check your symbol map.

This article explains what the NinjaTrader log errors "unknown symbol" and "Could not find symbol for contract id" mean, why they stop Replikanto from copying trades to your follower accounts, and how to fix them by updating NinjaTrader's instrument database.

Symptoms

When NinjaTrader is unable to identify the instrument of trades being placed in TradingView, errors like these start appearing in the NinjaTrader logs (Control Center > Log tab):

2025-01-XX XX:XX:XX:XXX|3|32|Order '123456789101112' received for unknown symbol ''
2025-01-XX XX:XX:XX:XXX|2|32|An execution for unknown symbol '' was received. Check your symbol map.
2025-01-XX XX:XX:XX:XXX|3|32|Could not find symbol for contract id '4399654'

The same underlying problem can also show up on its own as a "Could not find symbol for contract id" message (with the contract's internal id) in the Control Center Log tab.

Why it happens

This most often happens right after a quarterly futures rollover, when NinjaTrader's instrument database has not yet been refreshed to the new front-month contract.
Without NinjaTrader's identification of the symbol, the trade can't be identified. Add-ons — ours or third-party — then don't work properly: the copy to the followers doesn't occur, leaving their accounts out of sync.
No add-on running on NinjaTrader is responsible for matching trade symbols. That responsibility lies with NinjaTrader itself.

How to fix it

1. Reset your instruments

Disconnect from any active connections in the Control Center > Connections dropdown.
Go to the Control Center > Tools > Database Management window.
Under the Update instruments section, make sure the General properties, Futures expiries and Symbol mappings options are checked, then click Update.
Restart NinjaTrader, then test again.

2. Make sure the new contract is available

If the new contract month is still missing after the update, roll it over in the same Tools > Database Management window: the grid under Rollover Futures Instruments shows each instrument eligible for rollover — click Rollover to move it to the next contract month. You can also type the next contract (for example, ES 12-26) directly in the instrument selector and press Enter.

3. Check the contract in Replikanto

The instrument shown in the Replikanto window must match the contract being traded on the leader account. If you trade from TradingView or Tradovate, keep in mind that NinjaTrader usually prompts you to roll over a few days before Tradovate does — see the rollover guide below before accepting NinjaTrader's rollover prompt.

If the error persists

Because this issue is in the NinjaTrader software, the best help comes from NinjaTrader's support team at support@ninjatrader.com. Ask for a human support agent to report the problem — NinjaTrader's AI support agent is currently unable to handle this particular issue.

Once NinjaTrader identifies the symbol correctly again, Replikanto will copy the trades as normal.

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