Force 180 "36 (STA INITIATED DISCONNECT)" problem

Hello folks
Since Saturday, an SM from my network started to disconnect from the AP. both the SM and the AP worked with firmware 4.4.3, yesterday I upgraded to 4.5 on both and the problem persists.
there are lines of sight between the SM and the AP (2.2km)
in the AP the frequency in use is the one that selects the "Automatic channel selector" as the best.
another 3 SM (force 180) hanging on the AP work perfectly.
in the SM status board I visualize the following:
Downlink RSSI: -53 dBm
Downlink SNR: 43 dB
UPlink MCS: MCS 14
Downlink MCS: MCS11
Link Quality (uplink): 100% (permanent)
Link Capacity (uplink): 80% (stable)
Ethernet Status: 100 Mbps / full

the problem is that the Ethernet Status changes to: DOWN! It connects and disconnects all the time and I cannot receive traffic at the gateway.
I can clearly connect to the SM remotely.

reviewing the SM syslog I found errors such as:
  Reason: 36 (STA INITIATED DISCONNECT)
  Reason: 33 (GPFs MISS)

I was reading another post on the topic "STA disconnect and GPF lost" and found that it could be the subject of: "You may be running into high interference".

I wanted to know if I am really facing an interference very close to the SM and to know if it is possible to detect it with any tool since the AP does not show me interference in the operation channel.
I am puzzled.

Hi,

Please open up a support ticket and provide the tech support dump. It will help to narrow down the issue.

Thanks,

Dmitry

Ok Dimitri, tnks a lot