ORBI Wired Backhaul not working

Hi everyone!

Im a proud owner of a orbi RBK50 (53) System.
I just moved to a news house so i had the opertunity to lay a wired backhaul network for my orbi system.
Happy that i was ...but 1 of my orbi doesnt preform well

The RBS drops its wifi connection and disappears from the network. I have scanned the wifi network and i see the mac adress of the RBS dropping and comming back up. This happends al the time.

In the RBR on the status page you see that the RBS is not connected and a few minuten later its connect.

I have search the internet for a fix and did the following things:

I tried to turned it to a wirrles backhaul but the problem is stil the same.

I did a clean wipe of the RBS true Tellnet

Gone back a frimeware and reflash the current frimeware

I used the reset button on the backside of the RBS

None of the above helped me out

RBR50 Settings:
Daisy-Chain Topology - Disabled

Implicit BEAMFORMING - Boosts WiFi speed, reliability, & range for all mobile devices - Enable

MU-MIMO - Enable

Fast Roaming - Enable

I have tried turining them on and if but there was no change.

So before i ship it back for warranty i want to know if my setup isnt the problem.

My setup is the following:

The problem is with the RBS50-2

1.modem/router from the provider.(i will refer it as Modem)
WAN/DHCP/NAT is running from here.
Wifi is turned of

PORTS:
1.1 one cable to netgear 8 port switch.

1.2 one cable to RBR50

2.
RBR50
PORTS:

2.1 cable from the Modem to RBR50 (explained in 1.2)

3. RBS50 - 1

3.1 One cable from switch  to RBS50

3.2 One cable from RBS50-1 to RBS50-2

4. RBS50 - 2 (this one is the problem)
4.1 recieving one cable from RBS50-1(explained in 3.2)

I have read on the forms, if you want to setup a wired backhaul you have to connect the RBS wirelles to the RBR.
If that is done. Connect the RBS directly to the RBR by ethernet.
When in the status page the wirles backhaul changes to Wired you can disconnect the RBS and put them on there place.

This worked for me but stil got the problem with RBS50-2

I think i have to turn it in for warranty but its to much of a drag haha.
so if anyone can help me?