The Permission Denied error on withdrawals generally means you have Two-factor Authentication (2FA) for deposits & withdrawals turned on and are entering it incorrectly or not at all.

If you are confident you are entering the correct 2FA code, see My Authenticator App 2FA code doesn't work for more details.

If the Global Settings Lock (GSL) is enabled on the account, you will be prompted to enter 2FA for funding even if you haven't set it up. In this case, you can just leave it blank.