Error 651 | Connection failed

What This Code Means

Where Users Usually See This Code

• WAN/PPP connection attempts
• Device network status dialogs
• ISP authentication and session setup
• After modem/router restarts or configuration changes

Why This Code Appears

• PPP authentication or negotiation failed
• The WAN link could not be established
• Name resolution or DHCP assignment failed
• A modem/router configuration mismatch prevented connectivity

What Typically Happens Next

• Internet access is unavailable
• Devices may connect locally but not reach the WAN
• Retry may succeed after restoring the failing layer

What This Code Is Not

• It is not always a router hardware defect
• It is not always caused by the ISP

Troubleshooting Checklist

• □ Confirm whether the issue affects one device or the whole network
• □ Restart in order: modem (if present) → router → affected device
• □ Check WAN status lights and the router status page if available
• □ Verify credentials and connection type (e.g., PPPoE) if applicable
• □ Test name resolution by trying a different DNS setting if appropriate
• □ If the issue persists, contact ISP or router vendor with the full error

Notes And Edge Cases