The extender had a period of not being used. When I plug it back in; it is only picking up the 2.4GHz signal and the blue light for the 5GHz does not come on. 

There has been a change in my house setup that is; I have a new internet provider and have gone from broad band in Australia to the NBN network. The router has remained the same.     I have followed the instructions for pressing the WPS buttons on both the router and the extender but this has not worked. I want resetting my router and nbn to be the last resort as I do not want to disrupt the household set up if at all possible, as it is working well. Really appreciate help for me to connect to 5GHz network.