Bip39 Online. Try to remember, there isn't any such detail like a “Improper” passphrase. Every single diverse passphrase you enter is actually a fully new wallet. Watch out when recovering your seed that has a passphrase. BIP39 specifies a list of 2048 words from which the mnemonic phrase is decided https://thebookpage.com/story4306139/bip39-words-https-linktr-ee-bip39-getting-my-bip39-passphrase-to-work