On each account, the first agent to open a position in a product holds that product until the position is flat. Until then, no other agent on that account can trade it, not even to reduce or close it. So two signals can't double your size on one account, or close a trade the other one opened.
What counts as the same product
The mini and the micro are one product: NQ and MNQ, ES and MES, YM and MYM, RTY and M2K, GC and MGC, CL and MCL. The same goes for silver, natural gas, the currencies, Bitcoin and Ether.
The contract month doesn't matter.
Other products are separate: an agent holding MES doesn't hold back one on MNQ.
Each account is separate too, so the same product on another account is free.
What you see
A signal turned away for this says another agent has it in Activity, with the agent that holds the product.
When it is free again
When the position is flat, however it closed: the agent's own exit, a stop or target, or your flatten.
Switching the holding agent off doesn't free it. The product stays with that agent until the position is flat, and while the agent is off it won't close the position for you, so flatten it yourself.
Deleting the agent, or changing its signal, instrument or account, frees it. The position then belongs to no agent, like one you opened yourself.
Your own trades
This rule doesn't apply to your own orders, so it never holds back flatten, flatten group or FLATTEN ALL. A position you opened yourself belongs to no agent, so any agent on that account that trades the product may add to it or close it. Those agents show it with not placed by this agent.
If two of your signals trade the same product on one account, whichever opens a position first takes the trade, and the other's signals for that product are skipped until it is flat. To have both trade, put them on different accounts. It is also why an account at its position cap holds that many different products.
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