If we are facing issue when we are placing order and it will show Authentication Declined Message then We can follow below steps to solve it
Issue(ScreenShots)
Solution
This issue is occur because of payment method if make payment by selecting invoice then we will not get any issue, if we make payment by using Credit/Debit Card then we will get this issue.
Steps to Solve the Issue
Login to Netsuite using Userid and password
Navigate to Commerce>Website>Website List
Edit the website
Click on Shopping Tab
Uncheck the PROCESS AN ONLINE PAYMENT WITH SALES ORDER CREATION checkbox.
Click on Save
Clear the Cache.