Q: Apple TV does not connect to a known wifi network

I have a second generation Apple TV that was bought in Lisbon and configured in Luanda, I have used it many times without problem.

I have not used it for about one year, now I am back home and just tried to connect it again, can not connect. The Apple TV does not find any wifi network. I have done this many times in the past. My connection is through an wifi router.

I have tried connecting by an Ethernet cable, it worked OK, restored it and tried again with wifi, no success. Left the Apple TV sleeping unplugged from the wall for few days, when reconnected again, it worked perfectly.

One week after, I am trying to use my Apple TV and again the same problem.

I would appreciate any suggestions.