← Full guide: Nest Thermostat Won't Connect — Power, Wi-Fi, App Checks

Classify the failure before you reset anything

For “Classify the failure before you reset anything”, what you see. Start with. Do not assume. Every Nest product is offline.

Start here

For “Classify the failure before you reset anything”, what you see. Start with. Do not assume. Every Nest product is offline. Check power, router, ISP availability, and Nest service status. That the thermostat alone has failed. Only the thermostat is offline. Record its exact screen message or help code and check its network status. That changing HVAC wires will restore Wi-Fi. The thermostat works locally but not.

What applies to this exact problem

What you see	Start with	Do not assume
Every Nest product is offline	Check power, router, ISP availability, and Nest service status.	That the thermostat alone has failed.
Only the thermostat is offline	Record its exact screen message or help code and check its network status.	That changing HVAC wires will restore Wi-Fi.
The thermostat works locally but not in the app	Check the correct Google Home or Nest home, app version, and account setup.	That a factory reset is the first step.
The thermostat also reports a power or battery problem	Use Google’s model-specific power guidance or qualified HVAC service.	That a generic voltage target applies to every system.

Check these first

Every Nest product is offline: Check power, router, ISP availability, and Nest service status.
Only the thermostat is offline: Record its exact screen message or help code and check its network status.
The thermostat works locally but not in the app: Check the correct Google Home or Nest home, app version, and account setup.

Fix it in this order

Every Nest product is offline: Check power, router, ISP availability, and Nest service status.
Only the thermostat is offline: Record its exact screen message or help code and check its network status.
The thermostat works locally but not in the app: Check the correct Google Home or Nest home, app version, and account setup.
The thermostat also reports a power or battery problem: Use Google’s model-specific power guidance or qualified HVAC service.
Check power, router, ISP availability, and Nest service status.
Record its exact screen message or help code and check its network status.
Check the correct Google Home or Nest home, app version, and account setup.

Evidence to keep

Device model/firmware — keep it with the evidence for “Classify the failure before you reset anything”.
LED/error state — keep it with the evidence for “Classify the failure before you reset anything”.
Router/network details without passwords — keep it with the evidence for “Classify the failure before you reset anything”.
App/account error screenshots — keep it with the evidence for “Classify the failure before you reset anything”.

Do not make it harder

Factory-resetting before checking simpler causes For “Classify the failure before you reset anything”, that can hide whether the underlying issue is actually resolved.
Posting Wi-Fi passwords or tokens in support screenshots For “Classify the failure before you reset anything”, that can hide whether the underlying issue is actually resolved.
Changing multiple router settings at once For “Classify the failure before you reset anything”, that can hide whether the underlying issue is actually resolved.

How you know it is fixed

The official record and your real-world result agree for “Classify the failure before you reset anything”.
You have enough written evidence to prove the issue is finished if it returns later for “Classify the failure before you reset anything”.

If this still isn't resolved

Vendor status/support State the unresolved issue explicitly: “Classify the failure before you reset anything”.
Router/ISP support if the network itself is failing State the unresolved issue explicitly: “Classify the failure before you reset anything”.
Warranty/replacement when hardware diagnostics point to a device fault State the unresolved issue explicitly: “Classify the failure before you reset anything”.

Parent-guide references

These references support the parent guide and escalation context. Verify provider-, model-, policy-, or jurisdiction-specific details before an irreversible step.

Need the complete context?

This page solves one branch. The parent guide covers the full decision, edge cases, alternatives, and related checks.

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