Sui uses optimistic concurrency control, meaning objects are locked when used in a transaction until that transaction is finalized or expires.

Even if you wait 3 seconds between transactions, if the previous one hasn't been finalized, the object remains locked. This means that transaction is still pending and holding exclusive access to the object.

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How to Check If an Object Is Available

Use the Sui RPC method:

sui_getObject

Check response for "status": "Locked" or "owner": "locked".

Example request:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "sui_getObject",
  "params": ["0x...object_id..."]
}

If locked, just wait more and retry later.

Hey, you are trying to do a transaction too fast and the objects got locked.

Try to send one transaction with the same objects at a time, if you send two transactions some validators might accept the first some might accept the second and you objects will be locked because each transactions needs 66.7% of validators and you might be getting only 50%.

=> just wait for the epoch reset, it's soon 🫡

Check more: https://forums.sui.io/t/beginner-tutorial-error-when-deploying-simple-sui-package/44842

The error means the objects your transaction uses are still locked by previous transactions not yet finalized. Even with delays, objects remain reserved until those transactions complete on-chain.

To fix:

1. Always confirm prior transactions involving the objects have fully finalized before using them again.
2. Check object status via Sui RPC to ensure they’re unlocked.
3. Avoid sending parallel or rapid transactions on the same objects.
4. Implement retries with backoff and finality checks instead of fixed delays.

This locking prevents conflicting updates and is normal in Sui’s object model. Proper sequencing and finality confirmation are key to avoiding JsonRpcError.

This error happens if you try and run two transactions simultaneously (e.g. start one before the previous one finishes). If you retry running the publish transaction, without running another transaction before or at the same time, it should succeed. You may also need to acquire more gas from the faucet (or wait a day – for the epoch to roll over – for the objects to get unlocked)

When you run a transaction that involves objects that your address owns (like the gas objects) validators reserve the latest version of the object to be used by the transaction it is signing. If you try and run two transactions simultaneously and they refer to the same object, then they will compete with each other for signatures from validators. In the happy case, one of the transactions wins, and runs, and the other transaction fails to get enough signatures. In the unhappy case, both transactions can fail to get enough signatures (if both got more than a third of the validator’s signatures, then neither can get over two thirds, which is the threshold), this is called equivocation, and from that point the objects that were inputs to both transactions can’t be used for any other transactions.

At the end of the epoch (they are roughly a day long – you can check progress to the next epoch change on https://suiexplorer.com), all locks are released, so you can use the objects again, but if you haven’t had an epoch change since you last tried, you will need to acquire more gas.