What is your network setup like?
- Is your Xbox connected over a wired or wireless connection?
- Go to pingtest.net - does it report any packet loss (Java is required for this test)?
- If you go into a command prompt (windows) or terminal (linux / mac) and ping any other site (i.e, google.com) from a computer, does it report packet loss?
- What is the MTU on your network? (Run network diagnostics on your Xbox, it should tell you.)
- What is your result on speedtest.net?
--
Disclaimer: I don't work for EA, just trying to help out.