Troubleshooting Credit Card Processing Error: POS LU ERR A3 102

Overview

The POS LU ERR A3 102 error occurs during credit card processing and indicates a communication or key validation issue with TSYS. This commonly relates to a problem with the automatically generated key.

Example Error Message

POS LU ERR A3 102

Root Cause

This can happen when the same Host Capture ID is used for both in-store (card-present) and eCommerce (card-not-present) processing. NX requires separate Host Capture IDs—one for In-Store and one for eCommerce. Using a single ID across both environments can cause key mismatches and trigger POS LU ERR A3 102.

Resolution Steps

1. Verify Merchant Account Configuration 
   • Review the merchant account setup in the NX Portal. 
   • Confirm which Host Capture IDs are currently configured for In-Store and eCommerce. 
2. Update the Merchant Account in NX Portal 
   • In Merchant Account settings, configure two distinct Host Capture IDs: 
     • In-Store Host Capture ID (card-present) 
     • eCommerce Host Capture ID (card-not-present) 
   • Save the changes. 

Testing

• After updating any merchant account settings you must perform a "Config Pay Device" on all stations with readers for those new settings to go into effect.
• Run a test credit card transaction from the device.

If issues persist please contact your Processor and NX Support.