Depositing Stellar Lumen (XLM) to Bitfinex requires both a deposit Address and a deposit Memo.
To make a Stellar Lumen deposit, you need to use both:
On the deposit page, the deposit address is shown at the top, with the deposit memo for each of your wallets shown below. To make a deposit to your Exchange wallet, for example, you will need to use the deposit address shown near the top and the deposit memo next to your Exchange wallet.
Please note: If you fail to include the deposit memo with your deposit your XLM will be lost forever.
Please contact support if you have any questions or concerns.