There are a couple of reasons why you might see error 400 when you try to withdraw your INCNT to an external wallet.
1. We need more information from you. Check that you have verified your email address and mobile phone number. Ensure that you have added your date of birth to your profile.
2. Your wallet address has been input incorrectly. Please make sure that you do not add any spaces at the beginning or end of the wallet address.
3. You might not have accounted for the transaction fee. For example, you will see on your dashboard that the transaction fee is 2%, that means that if your INCNT balance amounts to $100 in AUD then you can only withdraw the equivalent of $98AUD leaving 2 % ($2 ) in the account to cover the transaction fees. (The fee mentioned here is purely for illustration purpose and may not constitute to the actual fee)
Hope that helps!