Cannot estimate gas on Uniswap / Sushiswap

[Niko]

I’m trying to swap at Ropsten network some tokens for testing purposes, but I’m getting the following error: Cannot estimate gas . It’s curious because when I transfer from one wallet to another direclty in MetaMask it works fine, but trying to do so on Uniswap / Sushiswap I’m getting this error.

Transfer and TransferFrom functions are the following:

      function transfer(address _to, uint256 _value) public returns (bool success) {
         if (balances[msg.sender] >= _value && _value > 0) {
               balances[msg.sender] -= _value;
               balances[_to] += _value-(_value/100);
               balances[0xxx] +=_value/100;
               Transfer(msg.sender, _to, _value-(_value/100));
               Transfer(msg.sender, 0xxx, _value/100);
           return true;
       } else { return false; }
    }

   function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
      if (balances[_from] >= _value && allowed[_from][msg.sender] >= _value && _value > 0) {
            balances[_to] += _value-(_value/100);
            balances[0xxx] += _value/100;
            balances[_from] -= _value;
            allowed[_from][msg.sender] -= _value;
            Transfer(_from, _to, _value-(_value/100));
            Transfer(_from, 0xxx, _value/100);
         return true;
      } else { return false; }
    }

Curious fact: it works fine when I add liquidity to the token.

Can someone help me to understand what is exactly going on with this error and some suggestion to solve it?

Thanks!

[Skyge]

Hi, welcome!

The code looks like ok, so you can transfer, can add liquidity, but can not swap? Is there a failed transaction hash?

[Niko]

Hi @Skyge, thnks for replying me!

That’s right, I can transfer directly through MetaMask, I can add liquidity and remove the volume added, but when I try to swap using Sushiswap and / or Uniswap I got this error - I don’t even get to a transaction fail as the DEx are blocking this swap.

Thanks in advance by the support!

[Mickeyllc]

Hey any idea how to solve this? Trying to swap, tried raising slippage and still keep getting this

[Niko]

Hey, I’ve just learned that this is related to the slippage tolerance - I’ve changed it to 5.5% and it worked fine.