Your inability to withdraw funds, such as USD, Bitcoin, etc. can be due to multiple reasons.
You might be shown a “Balance is insufficient for a withdrawal” error In that case, check the following:
Do you have any orders open/pending? You cannot withdraw the fiat currency used in an open/pending order
What to do: cancel open orders
Do you have a negative balance in any fiat or crypto/digital asset? That prevents fiat withdrawal from the account
What to do: Deposit the funds in fiat or crypto/digital asset that has a negative balance. You can make up for the negative balance by exchanging other fiat currencies or digital assets/cryptos.
You cannot withdraw an amount that is bigger than the account balance
What to do: Enter a lesser amount that can be withdrawn