Orbi network drops frequently and Satellite showing poor backhaul status

Hi,

I have following setup

RBR50 - Setup in basement

RBS50-1 - Setup on the first floor which is above basement

RBS50-2 - Setup on the second floor

I have 500Mbps fiber optics line coming to ISP router and the ISP router is connected to RBR50. Distance between any two units is less than 30 feet and there are no concrete walls in between. All walls are wooden.

2.4 GHz is on channel 11 fixed and 5GHz is on channel 48 fixed.

* root@RBR50:/# config get wan_lease    —> It gives me 750. I have reduced it from 86400.

I have multiple issues here.

1. One of my Satellite shows poor backhaul status no matter where I place it. I changed it place from one room to other and placed it right next to RBR50 but the status remains poor after showing it good for couple of hours after restarting it.

2. The internet is dropping frequently especially between 10 and 11 pm. When I checked the log, I see DoS attack around the same time and right after that attach, it goes down. It happens every single day without exception. The network comes back up in 2-3 mins and sometimes it comes back up within 1 minute also.

3. The internet drops randomly during the daytime with same pattern but there is no specific time.

4. When I upgraded the firmware to 2.5.1.16 recently (on 6/5/2020), It made me crazy by dropping so frequently, I had to go back to older version (2.5.1.8) of firmware. It got better since then but I still have the above problems.

Everytime when I change anything I rest all the devices including ISP router.

This is my second set of this bundle as I had to return the first one to Costco for the same reasons. Please someone help me fixing these issues. This impacts my ability to work from home severely.

TIA,

CAH