COMMUNICATION ERROR | Host communication failed

What This Code Means

Where Users Usually See This Code

• Card-present checkout prompts
• Settlement and batch close operations
• Terminal pairing and configuration screens
• During terminal software or key updates

Why This Code Appears

• A payment decision was returned by the issuer/processor
• Connectivity prevented reaching the host
• Device configuration or keys were incomplete
• A local device state blocked completion (paper out, update required)

What Typically Happens Next

• The terminal displays a prompt and aborts the flow
• The POS may ask to retry or use a different method
• Final status must be confirmed in the processor record

What This Code Is Not

• It is not always a decline
• It is not safe to re-run a card without checking for duplicates

Troubleshooting Checklist

• □ Determine whether the message is a decline or a technical failure
• □ Confirm connectivity (Ethernet/Wi‑Fi/cellular) and signal quality
• □ Check for required updates or key loading status
• □ Confirm batch/settlement state if the error appears at close
• □ Verify merchant configuration identifiers (TID/MID) if shown
• □ Escalate with logs/receipts to the terminal vendor or processor

Notes And Edge Cases