Bip39 Checksum. You should then do a primary Restoration with a command just like the just one down below. (This command uses a sample wallet file bunlded with BTCRecover) Entropy is a sophisticated element. Your mnemonic can be insecure if this feature is used incorrectly. Read more BIP-32 hierarchical deterministic https://socialbraintech.com/story4566312/bip39-wallets-https-linktr-ee-bip39-the-basic-principles-of-bip39-mnemonic