Ethereum wallet addresses are generally divided into two categories:
1. Regular addresses
2. Smart contract addresses
With regular Ethereum addresses, the fee of Ethereum transaction simple to calculate. The main issue is when tokens are sent to smart contract addressees due to lack of transparency of the transaction fee, which may result in "Out of Gas" error due to insufficient balance.
Therefore, it is recommended that, to send Ethereum to your smart contract address:
1. Send your Ethereum from HollaEx to wallets such as JAXX or MyEtherWallet etc.
2. Send it to your desired smart contract address.