@AntoZ 

Hi, nice to see you again.

May I know how long have you had these Deco units? and Did this disconnection last for a long time?

Is there any chance that you could provide a floor plan map with the location of each Deco P7/P9?

Have you ever checked how often one satellite Deco will turn flashing red and become offline from the Deco APP?

Thank you very much.

Wait for your reply.

Hi  @David-TP ,

I've had the DECO P7 from approx. 3 years
Instead the DECO P9s from approx. 6 months
 

I see the Deco satellites out of order (all smart-home connected devices are out of order) but I can't tell you the fail sequence.
Attached a map. The walls are in concrete and there is no direct communication between the ground floor and basement.
Thank for support.

  @AntoZ 

Hi, Thank you very much for the message and sorry for the delay.
Is the current network layout still the same as the above reply:
https://community.tp-link.com/en/home/forum/topic/601048?replyId=1184828

Could you please send an email to support.forum@tp-link.com with the following details:
1. some screenshots of the network map and signal source strength, such as:

2. How often would the disconnection repeat within one day?

3. Since you have installed the debug firmware, next time the disconnection started again, would you please note down the exact time and export the system log from web UI to the email?

Thank you very much.

Best regards.