EDC settlement "technical error" means the primary network is down and card processing is operating in standby mode (approvals only, no settlement).
Resolution: Try the settlement again later (next day if necessary) or contact your EDC merchant processor for current status. You may also need to restart the PC to reset the connection from standby to primary network. Also make sure the date/time for the PC has not been altered. If error is due to a specific transaction, make sure cashiers are not entering CCV codes in error into the approval code box which will invalidate the charge. The AP box is for autogenerated codes when transaction is approved or for entering an approval code obtained through voice authorization before swiping the card.
Note: If you are using Vantiv/Worldpay as your merchant processor (recommended), you may also receive a message "floor limit exceeded" when processing transactions in POS in standby mode. Each store location has a floor limit when operating in standby mode (approvals only, no settlement). If this occurs you will need to call the processor for voice authorization when the transaction amount exceeds the floor limit.