@DecoRonn
Hi, have you tried to manually add this unit on the Deco APP by clicking "+"> Add a Deco unit?
If it fails again, can I have a picture of the error message on the Deco APP?
After that, could you please help me run the following test:
1. switching the Deco X20_V2 as the main Deco.---How to Set up the Satellite Deco or a new Deco to be the Main Deco
2. try to add the other satellite Deco X20_V2 again on the Deco APP.
By the way, I noticed the current firmware of your Deco X20_V2 is on 1.0.3. The latest firmware for Deco X20_V2 is 1.2.3 Build 20230906.
It is also suggested to manually update the firmware to the latest version via web UI first:
Deco X20(US)_V2_1.2.3 Build 20230906
How to Update the Firmware of Deco
Thank you very much and best regards.