Questions tagged [kovan]

Kovan is a new testnet for Ethereum using Parity's Proof of Authority consensus engine, which is immune to spam attacks as Ether supply is controlled by trusted parties and provides a consistent 4 second block time.

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Function to store the strings from an api in an array and print the strings I want

I have this smart contract: *//SPDX-License-Identifier: MIT pragma solidity ^0.8.7; import '@chainlink/contracts/src/v0.8/ChainlinkClient.sol'; import '@chainlink/contracts/src/v0.8/ConfirmedOwner.sol'...
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0 answers
50 views

Fail with error 'SafeMath: subtraction overflow'

I am trying to use the "create" function from an LSP smart contract from the UMA protocol but I can not use it it always returns the "Fail with error 'SafeMath: subtraction overflow'&...
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2 answers
23 views

initial transaction reverted, but cannot rebroadcast due to error: Transaction with the same hash was already imported

I'm trying to deploy my project to Kovan and the initial deployment tx reverted, but any attempt to deploy again is stopped by this error. Shouldn't the fact that my initial tx failed remove it from ...
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15 views

Question about finding token addresses to insert into a .sol Contract function

Ok so I have a .sol Contract that is trying to find arb between 2 dexes I'm utilizing the Kovan Test Network - this is the function function estimateDualDexTrade(address _router1, address _router2, ...
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9 views

Signed transaction reverts Kovan

I am trying to send signed transactions against a smart contract in the Kovan network. I can send transactions which do not change the state of the EVM and they work fine but I can not get ...
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48 views

Get the connected accounts to a specific network from Metamask using web3.js

I am creating a dApp on Kovan Testnet. Can anyone tell me how can I get the connected accounts to Kovan from metamask using web3.js? I can get the accounts added to the Metamask using this, const ...
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1 answer
195 views

How to get Sushiswap and Uniswap prices from API for WETH/DAI on KOVAN?

Where can I find APIs to query data of WETH/DAI Prices on Uniswap and Sushiswap? For the mainnet, there is thegraph.com where one can query price data with pre-defined GraphQL queries, but I can't ...
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38 views

Gas estimation reverts

I am quite new to blockchain programming and am trying to estimate the gas cost of calling a function from a smart contract. I am using Web3 js and the Kovan network through an Infura node. What am I ...
1 vote
2 answers
356 views

How to get failed transaction status code by using python web3?

Given transaction hash, i want to fetch Status code ('45' in this case, refer below image) with which transaction has failed using python web3.py. I already tried these methods, they don't seem to ...
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2 answers
637 views

What is this STF error when trying to use a function in a contract

I know there are many similiar questions but i can not figure out how to implement the 'approve' part in. pragma solidity ^0.8; pragma abicoder v2; import '@uniswap/v3-periphery/contracts/libraries/...
1 vote
1 answer
118 views

How can I call a deployed smart contract on Kovan using Python?

The smart contract was written and deployed on Kovan using Remix IDE and injected Metamask Kovan test network account. However, I'll need python to deal with large input of a function in the smart ...
0 votes
1 answer
45 views

contract has not been deployed to detected network (network/artifact mismatch) when use truffle console --network kovan

i'm trying to call a function from contract that i deployed to kovan network, then when i used the truffle console --network kovan and tried to deploy my contract, it says that this contract has not ...
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247 views

How to get detailed error for ValueError: {'code': -32016, 'data': 'Reverted', 'message': 'The execution failed due to an exception.'}

I deployed my Fund_me smart contract on Kovan testnet and I tried to call the withdraw function on it using web3, but I'm getting the error ValueError: {'code': -32016, 'data': 'Reverted', 'message': '...
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0 votes
1 answer
340 views

Can't get Kovan testnet from Faucets.chain.link

I'm trying to get the ETH -> USD price from ChainLink but it's code requires the Kaven testnet. But the problem is that the https://faucets.chain.link website isn't working correctly and it sends ...
1 vote
2 answers
221 views

Error: This contract may be abstract, not implement an abstract parent's methods completely, not invoke an inherited contract's constructor correctly

Injected web3 Kovan 42 network Remix IDE This is from the freecodecamp.org tutorial on youtube Here is the code : // SPDX-License-Identifier: MIT pragma solidity ^0.8.7; import "@chainlink/...
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1 answer
93 views

Kovan Test Net: not receiving test LINK

I tried to receive Link on the Kovan testnet two different ways, with the same result- No error message, it just continues to load endlessly. https://kovan.chain.link/. a) "Send me 100 test link&...
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134 views

problems deploying a contract on the Kovan network

Good evening, a couple of days ago I was able to execute this command without any problem and today, suddenly, I got this error. I don't understand what it means by "insufficient funds". ...
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202 views

How to query Uniswap API to get cryptocurrency pair price on ethereum kovan network returns call revert exception error

I am currently trying to request a currency pair price from two tokens published on Uniswap at: https://app.uniswap.org/#/pool/10341?chain=kovan. Following a tutorial, I managed to successfully ...
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1 answer
1k views

Can I exchange test kovan eth to main eth? [duplicate]

I have some test eth. But I don't know how to use them. Can transfer as real eth Or what I have to do that please help me. Or I can sold them. In that case at how much cost can I sold.
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198 views

How do I listen to changes for an ethereum address using websockets + RPC eth_subscribe method + postman

I am trying to listen for changes in a wallet balance on the Kovan testnet , so I have connected to a Kovan node using a node provider's websocket endpoint, I have no errors connecting, and no errors ...
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3 answers
620 views

Kovan Chainlink Faucet - Unable to locate the transaction hash

Etherscan says "Sorry, We are unable to locate this TxnHash" when sending LINK using both https://kovan.chain.link/ and https://faucets.chain.link/kovan Waiting for a long time already but ...
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0 answers
192 views

ProviderError: Transaction with the same hash was already imported

I'm deploying upgradeable contracts on Kovan, but every time I run my deploy script I get the error. I'm using Hardhat. My deployment script const fs = require('fs') async function main() { let ...
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4 answers
283 views

Error: Private key does not satisfy the curve requirements (ie. it is invalid)

I have a project working fine on truffle but when migrating to Kovan network, Getting the issue "Error: Private key does not satisfy the curve requirements (ie. it is invalid)" project is an ...
1 vote
1 answer
290 views

Troubles interacting with Chainlink node on Kovan

I've been following instructions on running a local Chainlink node on Kovan. My environment is configured to Kovan through websockets via Infura and the node is both running and successfully accepts ...
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1 vote
1 answer
4k views

Where to find and how to get Kovan USDC testnet tokens

I need USDC Kovan testnet tokens transffered to this address 0x2E9b971e336C825BC41b9FE87376E74f0B3345FE for testing purposes. Token contract for this token is https://kovan.etherscan.io/token/...
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0 votes
1 answer
66 views

0x Kovan API returning 503 responses?

We have been using the Kovan 0x endpoint (https://kovan.api.0x.org/swap/v1) for a few months without trouble, but just started receiving HTTP 503 responses back today. Is the endpoint still supported ...
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57 views

Kovan Network - Transaction has been reverted by the EVM

i'm relatively new to web3 and Ethereum. I'm trying to approve a contract on the Kovan network, which requires 1 DAI to make this transaction. const segmentPayment = await gameContract.methods....
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430 views

How to get the contract address based on the transaction hash?

I have the following code which returns the tx hash but when I call upon the receipt it returns null and thus cannot extract the address: const privateKey1Buffer = Buffer.from(privateKey1, 'hex') ...
1 vote
1 answer
210 views

Chainlink "Any API" Returning 0

I want to use the chainlink API features but I can not get the data. When I try to execute requestEthereumPrice function I get "uint256: 0" I am using Kovan test net and metamask. pragma ...
1 vote
1 answer
642 views

Connect local React frontend to contract on testnet (e.g Kovan)

I am new to this community and I had a question, in my opinion I think basic, but I have not found much information, see if you can help me. I have been developing smart contracts, both in Remix and ...
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2 answers
1k views

Cannot obtain Kovan testnet Ether

Does anyone else have issues obtaining kovan ether? I have tried the following links only to recieve 0.01 Keth increments from app.mycrypto.com (when the site is up). The github sites do not respond ...
3 votes
4 answers
948 views

I keep getting nonce is too low when using truffle to call functions on contracts even though this works fine on remix.How can I fix this

I keep getting the nonce is too low when running functions with sub transactions on the kovan test net is there a way I can stop this from happening?these sub transactions are making transactions with ...
1 vote
1 answer
92 views

I'm connecting to the wrong network but my configuration seems right

Trying to run truffle console I got this typical error: I've checked my configuration and it seems OK to me (I don't know why truffle is trying to connect to 127.0.0.1). Here you can see my project: ...
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2 votes
1 answer
39 views

Is there a decentralized way to intercommunicate between two Ethereum networks?

If I have Contract A deployed to the Rinkeby Test Netwok If I have Contract B deployed to the Kovan Test Netwok Then, can we program the contracts to interact with each other like Contract A invoking ...
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1 answer
984 views

Not receiving LINK from Chainlink kovan faucet

I attempted to get funds from kovan.chain.link to my metamask address and the money did not come through. I got some errors as seen here: https://kovan.etherscan.io/tx/...
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1 vote
0 answers
163 views

Gas Estimation Error - Swap Contract

I'm working on developing a contract that automatically performs a swap and have been having an issue with the swap function. I finally got the contract deployed on Kovan, but have been getting the ...
1 vote
0 answers
59 views

Contract method works on local but not on testnet

The following method, which works perfectly fine on my local ganache. function someMethod() external view returns ( bool someValue, uint256 lastIndex, uint256 totalTokens ...
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1 vote
0 answers
49 views

AAVE Protocol v1 issue on reserve addresses with compound ctoken addresses

https://kovan.etherscan.io/tx/0xa7f5e857d1a9ecb4aca0714b24a70ca0942cc1a656c8e09b6d01bab9af4ec9e5 I am trying to make a transaction from DSProxy (Smart Wallet) on a contract https://kovan.etherscan.io/...
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334 views

Issue with `TRANSFER_FROM_FAILED` when calling Uniswap contract - but I am approving the token!

My code is pretty simple function swapForEth(address tokenAddress, uint amountIn, uint amountOutMin, address to, uint deadline) external onlyOwner payable { require(IERC20(...
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2 answers
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Exception:Reverted when swap by smart contrat with uniswap

Here is my code pragma solidity ^0.8.2; import "https://github.com/Uniswap/uniswap-v2-periphery/blob/master/contracts/interfaces/IUniswapV2Router02.sol"; contract Test_Swap{ address ...
2 votes
2 answers
4k views

"Invalid Chain Id" on Kovan testnet

I'm attempting to initiate a transaction (transfer of ETH) from my main account to a test account on the Kovan Testnet, but I'm getting the error Returned error: Invalid chain id. from the following ...
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1 answer
605 views

'Transaction nonce is too low. Try incrementing the nonce.' while following truffle tutorial

I ran into a nonce error on the last leg of this tutorial : https://www.trufflesuite.com/boxes/flashloan-box I also supplemented the tutorial with this video on yt(fyi b/c some of the code comes from ...
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0 votes
1 answer
362 views

Transaction not showing on Kovan etherscan even after its status showed transaction mined and executed successfully

I have my contract deployed on Kovan Testnet and from remix IDE I called one of the functions of my smart contract through remix itself. Now, the status of transaction shows "transaction mined ...
1 vote
0 answers
226 views

Is kovan network died? [duplicate]

Kovan's network faucet is inactive. I have only found a few "faucets" that give me 0.01 or 0.1 test Ether every 24 hours... https://faucet.kovan.network This is the Kovan Token contract. Its ...
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3 votes
1 answer
3k views

Cant find sushiswap router address for Kovan testnet

Can anyone get me a routerV2 address for sushiswap on Kovan? The address given on sushi page is incorrect.Thanks
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2 answers
292 views

Deploy contract to Kovan with brownie and infura

I'm trying to simply deploy a smart contract in Kovan network, i've used the export of the ID using export WEB3_INFURA_PROJECT_ID=xxxx but i'm getting this error ValueError: The method ...
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2 answers
1k views

Seamless process to obtain test ether from faucet? [duplicate]

I am unable to successfully "Buy" Ether from a faucet for Ropsten or from Kovan. Is it me or do most people have issues setting up a testnet using Ropsten and/or Kovan? Can anyone help me ...
0 votes
1 answer
669 views

Chainlink Price feed Main contract points to Kovan. Why? [closed]

I'm setting up price feeds with Chainlink. https://docs.chain.link/docs/ethereum-addresses#mainnet This page has sections: Mainnet, Rinkeby, Kovan. Under Mainnet.. Clicking a pricefeed takes me to .. ...
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0 votes
1 answer
181 views

ETH transactions to presale contract keep failing

I'm trying to send some ETH to a presale smart contract on Kovan. Allowance has been set with presale address as a spender - with the exact same amount as the tokens allocated in the presale contract. ...
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2 answers
1k views

Unable to interact with a contract on Kovan network on Remix IDE

I am working on a project and I have successfully deployed a smart contract on Kovan test network, but for some reason, I am not able to interact with it in JS code. So, now I want to access it ...
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