Transaction failing due to can't estimate Gas Cost on Polygon

Question

I have a function

function tokenValue( address _token, uint _amount ) public view returns ( uint ) {
        return _amount.mul( 10 ** IERC20( MY_TOKEN ).decimals() ).div( 10 ** IERC20( _token ).decimals() );
    }

To convert the decimals of one token into my token. However, when trying to call this on the deployed contract in a hardhat console, I get this error

  reason: 'cannot estimate gas; transaction may fail or may require manual gas limit',
  code: 'UNPREDICTABLE_GAS_LIMIT',

In my hardhat.config I have a manual gas limit of 2100000 so I'm not sure what I'm doing wrong here.

Answer 1

Due to this closed issue solution approach comment https://github.com/ethers-io/ethers.js/issues/1232#issuecomment-853726035 about UNPREDICTABLE GAS LIMIT problem, you have to remove gasPrice from your payloads to simplify eth_estimateGas.

Polygon also is sometimes returning 0 from estimation gas without no clue why which may also lead to problems UNPREDICTABLE GAS LIMIT.