cannot approve contract to ERC-20 token due to ProviderError: HttpProviderError error

Question

OracleSwap is a DEX that is a fork of Uniswap.

The end goal is I am trying to add liquidity https://docs.uniswap.org/contracts/v2/reference/smart-contracts/router-01#addliquidity

In order to do this, first we need to approve the OracleSwapRouter contract to spend the erc20 token.

I get below error when I am trying to approve to OracleSwapRouter in songbird (EVM compatible) network so that I can provide liquidity on the farm. I am not sure if this is an RPC rate-limiting issue or if something is wrong with the code.

ProviderError: HttpProviderError
    at HttpProvider.request (<path>/node_modules/hardhat/src/internal/core/providers/http.ts:78:19)
    at LocalAccountsProvider.request (<path>/node_modules/hardhat/src/internal/core/providers/accounts.ts:181:36)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async EthersProviderWrapper.send (<path>/node_modules/@nomiclabs/hardhat-ethers/src/internal/ethers-provider-wrapper.ts:13:20)

Any help is appreciated. Thank you in advance

Relevant links

oracle erc20 token --> https://songbird-explorer.flare.network/address/0xD7565b16b65376e2Ddb6c71E7971c7185A7Ff3Ff

contract to approve (OracleSwapRouter) --> https://songbird-explorer.flare.network/address/0x73E93D9657E6f32203f900fe1BD81179a5bf6Ce4

Below are the relevant code snippets

  const OracleSwapRouterContract = await ethers.getContractAt(OracleSwapRouterAbi.default,
"0x73E93D9657E6f32203f900fe1BD81179a5bf6Ce4");

const oracleContract = await ethers.getContractAt(oracleAbi.default,  "0xd7565b16b65376e2ddb6c71e7971c7185a7ff3ff");

 await oracleContract.approve(
      "0x73E93D9657E6f32203f900fe1BD81179a5bf6Ce4",
      oracleBalance
    );

The below code gives me the balance for the account so I know oracleContract is not the problem.

  const oracleBalance = await oracleContract.balanceOf(SONGBIRD_ACC);

my hardhat network config

songbird: {
      url: "https://songbird-api.flare.network/ext/C/rpc",
      chainId: 19,
      accounts:
        SONGBIRD_PRIVATE_KEY !== undefined ? [SONGBIRD_PRIVATE_KEY] : [],
      gasPrice: 900000000,
    },

Answer 1

You can add some lines to node_modules/hardhat/internal/core/providers/http.js to debug. After every isErrorResponse check, add: console.log(response) or console.log(jsonRpcResponse).

Most likely it's an error inside your contracts or deploy script (or both).