Following this topic since we are transitioning to customer portal 2.0 soon.

Hey there! Pre-authorization errors in the customer portal (or Aspire) are caused when the issuing bank, or our payment provider, cannot validate the card details. This can be caused by a few different things:

• Inaccurate card information. Any information, including the card number, expiration date, or billing name/address, etc., being entered inaccurately and/or not matching what the issuing bank has on file can cause a pre-auth error. Notably, CVV mismatches have their own error code, so that’s probably not the concern here. 
• One-time use cards. One-time use cards will fail in both the customer portal and Aspire as they are only authorized for a single, specific amount, which causes a failure when our payment provider validates the card information as part of the payment process/security check. 
• The issuing bank. Occasionally, there can be a problem with the bank related to the card. This is a rare case, but if you’ve checked card information and verified this isn’t a one-time use card, this is something our payments support team can help investigate. Logging a ticket with our Care team can get this process started. 

I recommend having the customer verify all card and billing information is accurate (if they uncheck “Use default billing information” in the portal when adding a payment method, they can review the name/address on file and check for accuracy), and ensure this isn’t a single use card. In my experience those two items resolve about 90% of pre-authorization errors.