If you make a crypto withdrawal to an address you have never used before you need to confirm or deny the transaction via email.
On the email, click the link to be redirected to a Vaultoro page with two options: confirm or deny.
If you click confirm, transaction is approved and this crypto address will be whitelisted for your account.
If you click deny, transaction is cancelled and crypto address will be blacklisted.
If you have denied a transaction you won't be able to approve future transactions and you will need to contact support.