A solid red LED indicates the Deco unit has a connection issue with the main Deco. It's not getting a signal.
Fix this first: power cycle the main Deco and the problematic unit.
- Unplug the power from the unit with the red light.
- Unplug the power from your main Deco (the one connected to your modem).
- Wait 30 seconds.
- Plug the main Deco back in. Wait for its LED to turn solid green.
- Plug the other unit back in. Place it closer to the main unit during this process.
- Give it a minute. The light should pulse blue, then turn solid green if it reconnects.
IF THAT DIDN'T WORK: If the light stays red or pulses yellow, the unit may have lost its configuration. You need to reset it. Press the Reset button for one second and release. The light will pulse yellow, confirming the reset. You must then re-add it as a new satellite Deco through the Deco app.
HEADS UP: For a stable mesh, keep satellite units within a reasonable range of the main unit. Walls and large metal objects degrade the signal.