Routers Error Code
Systems & Devices
Routers
Error 720 | PPP control failed
Industry
Systems & Devices
Canonical
/systems/routers/error-codes/error-720/
Last Updated
Feb 27, 2026
Summary
A PPP control protocol could not be negotiated during connection setup.
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What This Code Means
Error 720 commonly indicates that a PPP control protocol could not be negotiated. It suggests the connection stack could not complete required protocol configuration to establish the session.
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
Some “router” errors are shown by the device OS or connection stack, not the router UI itself.
Related Codes
8 links
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