Please Help My Metal 2shpn AP SSID disappear everyday

I purchased rbmetal 3 weeks ago and the first time i used the device the ap ssid disappear 2 times a day, the only

solution was to unplug the power adaptor from the outlet. I configured my rbmetal-2shpn as WISP AP for outdoor use.
I tried upgrading the routeros from 5 to the latest 6.22 version and still same thing happen. I am very frustated

now since the device i bought is brandnew, i tried to lower the tx power setting to 17dbm, country to US, channel

width to 20mhz but still didnt solve anything until now. I tried resetting the configuration and revert the tx

power back to default and schedule a reboot during midnight but still no luck.

Please help me I have only 4 clients connected to my ap and the furthest client is 700m with clear line of sight

you can see my configuration below and tell me what is wrong with my configuration or it is a hardware problem?

Thanks