MacBook Air 5GHz WiFi

Hello,

I have been having a particular issue with my WiFi network that prevents me from joining a 5GHz WiFi network. My router supports 2.4GHz and 5GHz, but I have only been able to join the 2.4GHz one.

The 5GHz network occasionally appears on my list of networks, but when I try to join it and enter the correct password, a popup shows up telling me that it couldn't be joined. I go back to 2.4GHz and I can access the internet and everything else is OK. My iPhone 5 (iOS 10.3.3) can join the 5GHz network and everything functions on that.

Is this a compatibility issue? Does this MacBook even support it or is there something else wrong?

Responses greatly appreciated.

I'll just chuck the Wi-Fi adapter section from System information here:

Software Versions:

CoreWLAN: 11.0 (1200.31)

CoreWLANKit: 12.0 (1200.31)

Menu Extra: 12.0 (1200.47)

System Information: 12.0 (1200.3)

IO80211 Family: 12.0 (1200.12.2)

Diagnostics: 7.0 (700.5)

AirPort Utility: 6.3.7 (637.6)

Interfaces:

en0:

Card Type: AirPort Extreme
(0x14E4, 0xE9)

Firmware Version: Broadcom BCM43xx 1.0 (7.21.171.131.1a1)

MAC Address: i think I'll leave this out

Locale: APAC

Country Code: X1

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

Supported Channels: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 36, 40, 44, 48, 52, 56, 60, 64, 149, 153, 157, 161, 165

Wake On Wireless: Supported

AirDrop: Supported

AirDrop Channel: 149

Status: Connected