TP-Link says a red Deco LED indicates a problem. On common models, solid red is a general issue, while exact behavior can differ by model.
What Solid red light means
TP-Link says a red Deco LED indicates a problem. On common models, solid red is a general issue, while exact behavior can differ by model.
What you may notice
- Wi-Fi has no internet
- One or all Deco units show red
- The app reports a unit offline
- Devices connect locally but sites do not load
Most likely causes
- 01The modem or ISP is offline
- 02The main Deco lost its WAN connection
- 03A cable is loose
- 04A satellite cannot reach the main unit
- 05A restart or update did not complete
Safe checks, in order
Start with the simplest non-invasive check. Stop as soon as the error clears; repeated resets can hide a condition without correcting it.
Check the scope
See whether all Deco units are red or only one. Test the provider connection separately if practical.
Inspect cables
Reseat power and Ethernet connections at the modem and main Deco.
Restart in order
Start the modem first and wait until it is online, then start the main Deco and satellites.
Check the app
Use the Deco app to identify the offline unit and any provider or configuration warning.
Avoid an early factory reset
A reset erases configuration and should come after model-specific support steps.
Know where to stop
Use only supplied power adapters. Do not reset or unplug a unit while the app says firmware is actively updating.
When to call a technician or support
Contact the ISP when the modem is offline. Contact TP-Link when the modem works directly but the main Deco remains red.
When you call, have the exact product or vehicle model, model year where relevant, the complete code or symbol, and when it appeared.
Where this information came from
We use the manufacturer's current published guidance as the starting point, then organize it into a safer, beginner-friendly sequence.
TP-Link Support — Deco LED color meanings Source last checked August 16, 2026. Manufacturer instructions and model manuals take priority over this independent summary.