Use a wired connection to your router. That worked for me, and it has worked for others on this forum. Do you still have an ethernet cable around? Connect that cable from your device (XBOX) to the router (Apple, or whatever you use). Restart both, and voila: it will work.
We had this problem all day. I used the troubleshooting outline from EA after doing a search of twitter (for news of network outage from EA - there was none), and of these bulletin boards (many other users with this problem!). These forums were more useful, because the information is more specific (...telling me to call my ISP is useless; not helpful). A user named UMBrynn identified the issue as most like a network degradation issue on 12-28-17, on another thread dedicated to 721 errors. I believe this is correct.
This means that, although your connection to the internet exists and is functional, it is not sufficient to support a connection to the game. It either is glitchy, or is is too slow, etc. Here, we have an array of devices using our wifi: iPads, phones, Nintendo Switch. I think that volume of devices, pulling data, detracts sufficiently from the strength of the wifi that it will no longer support the huge demands of BF2 on our XBOX.
Why EA does not simply tell us the particular problem, rather than using a goofy Error Code, is quite beyond me. Why the wifi connection worked for a week, with our XBOX, until today, is also beyond me.
Still, my family thinks the game is awesome. Well worth the hour or so it took to fix this!
See you in multiplayer BF2 combat,
MrShakespeare
Saint Louis, MO
