Problem with metal 2 wireless network

Hi
I used a metal 2hspn with antenna. metal is in a simple network and work in ap bridge.
my problem: when i am in a low distance of metal i can connect and get IP. about 4 or 5 meters. but in more distance more than 5 meters i can see network and SSID but i can’t connect to it and i get an authentication error and i can’t get an ip.
i checked freq and channel but nothing happen.
any idea?
if anyone can help we can do it with Any desk
email: mahdikhosravi1375@gmail.com
Telegram: @mhdi_khosravi
Screenshot (149).png

I’d select the band to be just “g/n” or just “only-n” and set the width 20Mhz. The first is not likely the issue but not helpful. But the “20/40Mhz” may be the issue, 2.4Ghz is only 20Mhz. Something to try.