@erdu 

Hi, 

Would its LED light turn flashing red as well? I have seen users report that the Deco was offline on the Deco APP, but the unit actually is green and working well.

Did it help if you unplug and plug the cable once?

Wait for your reply and best regards.

  @erdu Some options to try first:

1. Is the Deco completely not working or is it showing up in the Deco app as wirelessly connected?
2. Have you tried using a different cable in case it's broken?
3. Have you tried connecting the ethernet cable to all the different ports on each Deco unit?
4. Have you tried plugging the Deco power supply into a different wall socket?
5. Have you tried using the known working power supply into the offline Deco to see if the power supply is broken?

Definitely need a better description of the problem if this doesn't solve your issue