# Error after few calls: Response errors; output already exists

**URL:** <https://forum.fuel.network/t/error-after-few-calls-response-errors-output-already-exists/1869>\
**Category:** Rust SDK\
**Created:** [February 21, 2023, 1:32pm UTC](https://forum.fuel.network/t/error-after-few-calls-response-errors-output-already-exists/1869 "2023-02-21T13:32:05Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![fuel](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.fuel.network/fuel/32/1677_2.png) [@fuel](https://forum.fuel.network/u/fuel)\
**Post date:** [February 21, 2023, 1:32pm UTC](https://forum.fuel.network/t/error-after-few-calls-response-errors-output-already-exists/1869/1 "2023-02-21T13:32:06Z")

</div>

Hi guys  
[Here is the code of the liquidator](https://github.com/sway-gang/sway-lend/blob/liquidator/services/liquidator/src/main.rs) for the swaylend app. It [calls `is_liquidatable` contract method in loop](https://github.com/sway-gang/sway-lend/blob/liquidator/services/liquidator/src/main.rs#L58), as an argument it [requires oracle address](https://github.com/sway-gang/sway-lend/blob/8937733fc2bf1590a7d6f1d5d3f0d10f9e71b3f7/services/liquidator/src/utils/market_abi_calls.rs#L34) which is used inside of `is_liquidatable` method. And the loop works a few times (like ~20 times) well, but after that it fails with that error

```auto
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: ProviderError("Response errors; output already exists")', src/utils/market_abi_calls.rs:39:14
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

```

But if remake the call as follows

```auto
 pub async fn is_liquidatable(
        market: &MarketContract,
        contract_ids: &[&dyn SettableContract],
        address: Address,
    ) -> bool {
        let tx_params = TxParameters::new(Some(1), Some(100_000_000), Some(0));
        let mut res = market
            .methods()
            .is_liquidatable(address)
            .set_contracts(contract_ids)
            .tx_params(tx_params)
            // .estimate_tx_dependencies(None).await.unwrap()
            .simulate()
            .await;
        if res.is_err() {
            res = market
                .methods()
                .is_liquidatable(address)
                .tx_params(tx_params)
                .simulate()
                .await;
        }
        res.unwrap().value
    }

```

We well have that error

```auto
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: RevertTransactionError("", [Call { id: 0000000000000000000000000000000000000000000000000000000000000000, to: 2c290844d5b996b32cdf10de4a5294868efc3608e966a809bb03b86b2fecb2c4, amount: 0, asset_id: 0000000000000000000000000000000000000000000000000000000000000000, gas: 100000000, param1: 632439795, param2: 10472, pc: 11664, is: 11664 }, Panic { id: 2c290844d5b996b32cdf10de4a5294868efc3608e966a809bb03b86b2fecb2c4, reason: InstructionResult { reason: ContractNotInInputs, instruction: Instruction { op: 45, ra: 16, rb: 18, rc: 19, rd: 17, imm06: 209, imm12: 1233, imm18: 74961, imm24: 4269265 } }, pc: 313116, is: 11664, contract_id: Some(4bf2826201fb74fc479a6a785cb70f2ce8e45b67010acfd47906993d130a21ff) }, ScriptResult { result: Panic, gas_used: 4878713 }])', src/utils/market_abi_calls.rs:47:13
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

```

Please help me to fix this error