NO CONNECTION | Host connection unavailable

What This Code Means

Where Users Usually See This Code

• At sale time when authorizing a card
• During batch close/settlement attempts

Why This Code Appears

• Internet outage or unstable Wi-Fi/Ethernet
• Firewall blocks outbound host connections
• Processor outage

What Typically Happens Next

• Transactions cannot be authorized until connectivity is restored

What This Code Is Not

• It is not a card decline by the issuer
• It is not a terminal tamper event

Troubleshooting Checklist

• □ Verify the terminal has network access
• □ Reboot the router or switch and retry
• □ Test with a different network (e.g., backup connection) if available

Notes And Edge Cases