Troubleshooting — Castle S4
Card Present › Castle S4 › Troubleshooting
Declined transactions, error messages, and device issues with step-by-step fixes
Declined Transactions
| Message | Meaning | What to do |
|---|---|---|
| Payment declined | Insufficient funds or card issuer blocked the transaction | Ask customer to check card status with their bank. Try a different card. |
| Transaction timeout | No response received from payment network in time | Check internet connection. Retry the transaction once. |
| Incorrect PIN — please try again | Wrong PIN entered | Ask customer to re-enter their PIN carefully. |
| PIN blocked | Card blocked after multiple incorrect PIN attempts | Customer must call their card issuer to unblock. Do not retry. |
| Customer card has expired | Card past its expiry date | Ask customer to use a valid card. |
| Try another card | Unsupported or unreadable contactless card | Ask customer to insert the chip instead of tapping. |
Error Messages
| Error | Meaning | Action |
|---|---|---|
| Device not activated | Configuration download failed during setup | Ensure stable Wi-Fi. Restart terminal. Open TWPayz POS app again. Contact TWPayz if persists. |
| Loading POS configuration failed — missing parameter file | Credential configuration error | Contact TWPayz support immediately. Quote the exact error message. |
| Loading POS configuration failed — check param config | Terminal lost internet connectivity | Reconnect Wi-Fi or Ethernet. Restart terminal. |
| Unexpected error | Unspecified system fault | Note the error. Restart terminal. Contact TWPayz support if it recurs. |
| Unable to print receipt — refill paper and press enter | Printer out of paper | Load new paper roll (see Print Receipts guide). Press Retry. |
| Reswipe card | Magnetic stripe not read correctly | Retry swipe or switch to chip/contactless. |
| Transaction exceeds ceiling limit | Amount above terminal's maximum transaction limit | Enter a lower amount. Contact TWPayz to adjust limits if needed. |
| Format error | Incorrect CVV entered during keyed entry | Retry with correct CVV. Check with cardholder. |
| EMV configuration file downloaded error | EMV configuration file missing or invalid | Contact TWPayz support immediately. |
| No result in Transaction History | No recorded transactions or reporting service issue | Check date filters. If clearly incorrect, contact TWPayz support. |
Device Issues
| Issue | Steps to resolve |
|---|---|
| Terminal screen is frozen or unresponsive | Hold the power button for 10+ seconds to force a complete shutdown. Release and press again to restart. All transaction data is retained. |
| Wi-Fi connection keeps dropping | Move terminal closer to router. Reconnect via Cradle app Wi-Fi settings. Consider switching to Ethernet for stable connectivity. |
| Printer paper jam | Gently open the printer cover. Remove all paper carefully — do not tear. Reload paper roll correctly (glossy side out, feeding from bottom of roll). Close cover firmly and retry. |
| Terminal won't power on | Ensure power cable is connected and dock is receiving mains power. Check rubber flap covers charging port correctly. Contact TWPayz if no response after charging for 1 hour. |
| App crashes on opening | Force-close the TWPayz POS app. Reopen. If it crashes again, restart the terminal. If issue persists, contact TWPayz support. |
To contact TWPayz support from the terminal: Tap the menu icon (top-left) → select Contact Details. All support contact information is shown on screen.
Or contact us directly: support@twpayz.co.uk | +44 20 3129 9840
Or contact us directly: support@twpayz.co.uk | +44 20 3129 9840