I was trying the hard reset the AP but can't able to. We couldn't able to brings this into controller. 2.4GHz is stable and power and 5GHz is not stable. Please help us to resolve it?
Sorry but that doesn't make much sense.... is the AP now connected to the controller or not.
You wrote that you are not able to connoct it to the controller BUT then you write that 2.4GHz is stable.
Please try to explain the situation and the questions that you have in more detail.
I'd strongly recommend that you either visit the official training or get help from a Extreme partner for a day so they could learn you the basics of the WLAN controller solution.