Hey all, I came across this issue about 3 days ago. Tried everything to get it to work but nothing... a day passed and an idea came up to my head.. What if I change my wifi router?
I had an extra router laying around and I plugged it into my xfinity modem and put my xfinity modem on Bridge Mode. After this I set up my "other" wireless router with my xbox and BOOM! Everything worked perfectly. No lag or errors at all.
This issue might have something to do with your routers. Maybe Comcast to be more specific. I always had issues with Comcast but once I changed my router, the error was fixed and I've been playing flawlessly since.
Not trying to lower any ISP's rep, but Comcast might need to step their game up with their modems and routers.
If if this helps you, spread the word!!