The simple answer: if a reduce-only order fails, 99% of the time the direction is opposite to your current position, or you do not have a position at all. OKX is very strict about reduce-only rules — it can only close positions, not open new ones. If you miss one check when placing the order, it will be rejected.
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Step 1: Check Your Position Direction
This is the most common mistake. If you have a long position, a reduce-only order must be set to sell. If you have a short position, it must be set to buy. If the direction is reversed, the system will directly report an error.
[What to do]: Before placing the order, check your current position direction.
[How to do it]: On the futures trading page, look at the 'Positions' panel and confirm whether your position is 'long' or 'short'. If it shows a long position, choose 'sell to close long' for the reduce-only order. If it shows a short position, choose 'buy to close short'. Do not guess — confirm before clicking.
[Done when]: You have confirmed 'long goes with sell' or 'short goes with buy', and the direction is not reversed.
Step 2: Check Whether You Have an Open Position
OKX rule: If you do not have an open position, a reduce-only order will fail immediately. If you have already fully closed your position but a reduce-only order is still pending in the system, that order can never be filled.
[What to do]: Confirm that you still have enough position to close.
[How to do it]: Check the 'Position Size' in the 'Positions' panel. If it is already 0, a reduce-only order will not be filled. Also, 'close all at market' is a reduce-only order by default, and it will automatically become invalid once the position is gone.
[Done when]: You confirm the position size is greater than 0, and the amount you want to close does not exceed your current position.
Step 3: Check for Conflicting Pending Orders
If you already have a pending reduce-only sell order and want to place another one at a better price, the new order may partially or fully replace the old one. OKX rule: orders with better prices are prioritized, and worse-priced orders are automatically canceled or modified. The total amount of all reduce-only orders cannot exceed the position size.
[What to do]: Go to 'Open Orders' and check whether other reduce-only orders are taking up the slot.
[How to do it]: Open the futures trading page, switch to 'Open Orders', and review all pending reduce-only orders. If there is an older order in the same direction with lower execution priority than the one you are placing now, the system will automatically cancel it. If you notice the old order suddenly disappears, the system did not glitch — it automatically cleaned it up for you.
[Done when]: You confirm that pending reduce-only orders will not conflict with your new order, or you manually cancel the old order before placing the new one.
Special Case: If You Are Using API Orders
If you place reduce-only orders through the API, there is one common pitfall: In net position mode, an attached take-profit or stop-loss protection order with reduce_only=True may be rejected, returning the error 'Reduce Only is not available'. This is OKX's restriction on algorithmic orders in net position mode.
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How to Verify After These Checks
After completing the checks above, place a reduce-only order again. If it is accepted, go to 'Open Orders' and check whether the order shows the 'Reduce-Only' tag. If it still reports an error, check whether other unfilled pending orders are occupying the closing amount, or whether your position has already been partially closed.
