I repeatedly keep getting kicked off!!

Hmm, try unplugging your modem/router and restore the factory defaults on the console. Hope it helps!

is your xbox wired or wireless? do yu use any headsets with your xbox?

I have tried both wired & wireless and both have the same issue!  Not sure why a headset matters, but I do use TurtleBeach X31s

Try to connect with the Turtle beach headset fully unplugged as they cause a lot of wireless interference due to the fact they broadcast over all 11 wireless channels.  The solution if this works is to move the usb reciever as far from your console as you can or seperate the reciever and the console with a reflective surface.  As for the wired connection the issue may be in the router what router/gateway/modem are you using as I'm not 100% the issue is fully the headset but it could be a factor, my final thought here is have you done any port forwarding or DMZ'ed your console?

I have had my TurtleBeach headset for over a year and never had any issues. I always use wired to connect, and was only trying wireless to see if it was my cable that was possibly bad.

Router: Linksys (Cisco) E2000  (Wireless N)

Modem: Motorola Surfboard 6120

No,I have not done any port forwarding

I would port forward or DMZ your console and see if that helps, the DMZ is the easier way and make sure the guest network is off on the e2000 as it defaults on.

Yea, im having the same exact problem but no headset. Also have tried, resetting router, and the xbox, as well as testing all the configurations... and i keep getting the same error code...

W: 0000-0021

X: 0400-F001

Y: 20A8-4840

Z: 0000-0000

ID: FFFF-FFFF

Dog, please create a new thread in which you answer these questions.

try connecting directly to your modem to rule out a bad router.  If it does it connected directly to your modem call your isp.  If not you may need to replace your router.

I doubt its my router, my other devices (i.e. Laptop, Desktop, iPhone, etc.) connected to it do NOT have any problems