If you're receiving a miner fee error it's because you don't have the balance needed to cover the transaction and the associated network transaction fee.
You'll need to deposit additional funds to cover the transaction fee. All transactions on Coinbase Wallet take place directly on the blockchain and as a result all users are subject to pay the miner fees associated with their wallet transactions.
This fee goes directly to the miners who maintain and confirm transitions on the blockchain’s network.
For more information about miner fees on Coinbase Wallet, please read our Help Center articles: