I have had the exact same error the other day on a Fritz!Box, too. Just received a spare box from my local Apple Store. They said, it must be my router or my router settings as they tested my box on three different routers without error.
Question: do you use DHCP or manual IP settings?
I will let you know, if I still keep getting this error 3609.
Yes I have also tried exchaging the box and my sister is experiencing the same problem. She found some answer on the net saying that certain models have this problem. My biggest one is that 1) I already exchanged it once and 2) that the warranty period is way over now.
I got the error both with DHCP and manual IP.
Had the same issues, got my originial AppleTV replaced yesterday - but the trouble with Wifi continued. So I did some investigation. Not sure if this is of help for anyone but it seems that I am able to provoke the "WiFi connection" drop. That's my setup:
- AppleTV 3rd Gen, Software Version 6.0.1; static IP address
- Airport Extreme 2nd Gen Software 7.6.4; Bridge Mode activated; static IP address; WPA2 enabled; SSID not broadcasted;
- A bunch of other Apple devices on the same Wifi network - all working without any issues!!
1st scenario: Mac-Address filtering/access control disabled on Airport Extreme
--> Apple TV finds and connects immediataly to the network.
2nd scenario: Mac-address filtering/access control enabled on Airport Extreme:
--> Apple TV does not find/connect to network (YES, correct AppleTV MAC-address has been entered into Airport Extreme's filter list)
Interesting additional observation: Using a LAN scanner software I get confusing results:
In the 1st scenario the AppleTV shows up with its correct MAC-address (together with the correct assigend static IP-address)
But in the 2nd scenario I get a strange result: The correct static IP address of the AppleTV is now assigend to the MAC-address of the Airport Extreme. VERY STRANGE!!
I reported this to Apple support today - they need to check and will come back.
Anyways - perhaps you can check if disabling the MAC-addess filtering/access control let Apple TV connrct to WIFi again.
In my case disabling solved the WIFI connection issue of Apple TV but is not an acceptable solution as I rely on MAC-address filtering/access control due to security reasons.