RB1200 stopped internet services

Rb1200 stops the internet service and removes all users, then after 10 to 15 minutes starts to service again.
but after 5 minutes same issue again.
network (Eth01 Ip = 132.18.0.1/16, Hotspot user and radius) network with issue
network (Eth06 ip =192.168.40.1/24 network local) work great!!
network conigurate with DCHCP and other configuration google DNS 8.8.8.8.
I did installed fan cooler, I did installed other memory without good result
I did upgrade and downgrade but the problem continues

I did copy of the script and installed it on an rb450 and everything works without errors
how I can fix?

ROS Version?
How much Bad Blocks on Flash?

ROS version 6.38.5
but the issue is not with rb1200
I found the issue but I don’t know how to fix
Detail:
My network is:
router RB1200(two network)
Local network 192.168.40.1/24(working without issue)
Wireless network 132.18.0.1/20) ips reserved from 132.18.0.2-132.18.5.1
DCHCP from 132.18.5.2 - 132.18.15.254

all cable are cat 6
from 1200 to GX5 gigabit swith (8 port)
from GX5 gigabit swith to netgear gigabit swith(8 port)
from netgear gagabit swith to poeSwith( in poe swith 4 antennas ubiquiti powerStation 2.4 ghz)
other poeSwith 3 antennas sectorial (3 antennas with 3 rb 433ah + 3 miniPCI r52hn)
in this case with use cable cat 6 directly from Gx5 gigabit swith to poeSwith
note the issue is only one sector antenna(
I did Change the antenna, change the rb and change the card mini PCI r52hn and the problems continue,other has routerOS 6.35)
The problem is when I connect more than 3 clients (rb sxt, rb532), network fail completely and the internet service stops working.

hello all, the issue not is the RB1200
the issue is in one ap, the ap cause all network fail

app start working but after time the ap fail, I did change the ap (another RB, another miniPCI CARD) but the issue continue
changed the data cable, changed the POE

issue continue
I’m using Mk sxt Litle for my clients