"Another Computer on this network has the same IP"

I made a huge mistake. I called Xbox support and expected them to be able to assist me. I spent 6 hours on the phone with them. I disconnected my router several times, unplugged it, did some changes here and there, I am not really sure what they are doing.

I think I can solve the problem on my own. I have a "modem router" AT&T Uverse all in 1. My xbox is running sluggish and giving me errors. I found instructions on the net, I can follow them. I am receiving a NAT error. I need to move my xbox to the outside of my router or to another port. Their incompetence was astounding.

ANYHOW after 6 hours of failure I am now getting this error (Attached). I have 1 Computer, a lapton,xbox old ipad and Samsung galaxy tablet that share the router. Prior to calling Xbox - I NEVER received this error. What s it? How do I fix this conflict?

That error is not a big deal.

You can read a bit about it here:
IP error problem....help appreciated guys

Turn your AT&T router off (unplug it).
(This should make the router forget the IP addresses that it had assigned to each device.)

Restart everything that was connected to the router.
(This should make each device forget the IP address that it was using.)

Turn your AT&T router on (plug it in).

Each device should automatically get a new/unique IP address from the router. Any device that fails to get an IP address should be restarted once more.