Direct answer
A complete failure should be separated into power or eligibility, the external path, and the component itself before any reset. For double NAT and router chaining, first compare both devices’ WAN/LAN addresses and trace the physical uplink.
What this covers
- double NAT and router chaining with this exact failure state
- Diagnosis across gateway router mode versus downstream router, mesh and modem bridge capability
- Customer-accessible observation, settings and external components
What it does not cover
- ×A displayed manufacturer error code with a different documented meaning
- ×Live electrical, sealed-system, internal battery-cell or gas repair
- ×A claim that every model exposes identical controls
Capture the exact failure state
ReversibleRecord whether the feature is absent, disabled, powered but unresponsive, or showing a message. Expected behavior: provide one intentional routing boundary without conflicting private subnets or inbound translation.
Isolate the component boundary
ReversibleCompare both devices’ WAN/LAN addresses and trace the physical uplink. Test the simplest supported configuration with unrelated accessories and optional services removed. Boundary to separate: gateway router mode versus downstream router, mesh and modem bridge capability.
Correct only the proven cause
ReversibleBridge one approved device or place the downstream system in access-point mode. Restore only the failed prerequisite or path; do not change working layers.
Verify and stop safely
ReversibleRepeat from a cold start and complete one normal use. Do not disable provider voice/security functions or expose admin interfaces.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Exact questions
Common follow-ups
What should I check first when double NAT and router chaining has this problem?+
Compare both devices’ WAN/LAN addresses and trace the physical uplink.
Why not factory-reset immediately?+
The useful boundary is gateway router mode versus downstream router, mesh and modem bridge capability. A reset can erase state without proving which side failed.
When should I stop troubleshooting?+
do not disable provider voice/security functions or expose admin interfaces.
Answer for the exact device and software version shown above.