My router is Archer C9 v3 (EU). I’ve been having problem with the 5Ghz channel SSID not being shown sometimes in my MacBook Pro 2017 model laptop. When I turn on my MacBook, the 5Ghz SSID shows and works perfectly. The problem occurs when for some reason the router gets restarted or I switch to a hotspot/any other SSID. After that I don’t see my 5Ghz SSID anymore. 

I have dug deeper into this problem. For those unfamiliar with MacOS, for your information MacOS has a system report option where  we can see different parameters of Wi-Fi Interface of the machine under Wi-Fi sub-section. So when I turn on my MacBook and the 5Ghz SSID is available, System report shows the below status:

Country Code: X0

Supported PHY Modes: 802.11 a/b/g/n/ac

Supported Channels: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144, 149, 153, 157, 161, 165

Here, the country code is detected as X0. Please note that I am based out of Dhaka, Bangladesh. But the X0 country code simply means that my Wi-Fi adapter of the MacBook could not identify the country/region. My Archer C9’s 5Ghz channel gives 4 channel options (36,40,44 & 48). Please notice that all these 4 channels are available in the supported channel list above.

Now, when my 5Ghz SSID disappears, the system report shows the below status:

 Country Code: BD

  Supported PHY Modes: 802.11 a/b/g/n/ac

  Supported Channels: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 149, 153, 157, 161, 165

Here you can notice two things, Firstly, the country code is detected as BD which is correct (Bangladesh). Secondly, the supported channels no longer have the 4 channels offered by my router. So I can assume that when the country code is wrongly detected, my MacBook shows the 5Ghz SSID, but, when it is correctly detected, it doesn’t show the SSID anymore. So I can conclude that my MacBook Pro shows the 5Ghz SSID based on wrong configuration/detection of region.  In the web interface of my router there is no option to change the region, I can only set the Time Zone which is configured correctly.

But it is also to be mentioned that, my iPhone detects the 5Ghz SSID all the time. So who’s at fault? My router or MacBook Pro? How to fix it?