my AC791L's wifi is turned off and is refusing to turn on. It's not returning to 2.4HGz or any other

Hello friends, my hotspot wifi is turned off and has refused to turn on . I logged on my computer interface to activate it but the device by selecting the 2.4GHz but it still remains on turned off after saving changes. The instruction says that the device must restart for changes to take effect but the device is not restarting at this particular change. I notice that the device restarted at everyother changes done on it and the changes were effected, but on this particular section of turning on the wifi, the device is not restarting and so still remains turned off, and as a result, I am unable to connect any device to it because it is not even discoverable.

I really need a solution to this problem and will truly appreciate your help. I am suspecting it needs something like flashing it since reset factory does not solve the problem. Pls help. thanks.