Need help....

My 86u is not broadcasting 5ghz network.

I have reset, reboot, reflashed to no avail.

The 5ghz light is still on, MAC address is available, disabled the 2.4ghz network, but using my phone or laptop, I am just unable to see the 5ghz network.

Mine is a China unit from TB, I have also changed region settings to Asia and Singapore to no avail.

Any help is greatly appreciated.