When customers place an order thru the web store and then get a message like "An unexpected error occurs while trying to process the credit card transaction", consider logging into your merchant account online.
Look into the list of rejected transactions and verify if the record(s) shows the following message:
• Tran Type = 3D Enroll Check
• Error Code/Description = 400-Error Processing Lookup Request Message, Invalid Merchant id or Processor Id (xxxx, xxxx)
This means that the authorization is being sent to the merchant in a 3D Enroll Check type instead of Pre-Auth type.
If this is the case, confirm if you have enrolled to the feature called VBV/MSC Enrollment Check (also known as 3D Secure Service).
Most often than not, this message is returned having enabled a preference in NetSuite but not eligible to the said service yet.
To resolve this, the tick box for Payer Authentication must be unchecked. This is found by navigating into Setup > Accounting > Payment Processing Profiles > edit the payment gateway used.