Hi, I've read several posts that seem the same.
At start-up I can't log in unless I go to test network connections first.
I get randomly booted off live and cant sign back in from within the game or the dashboard and can only do it from within the test network connections.
This problem only happens when I manually configure the required UDP, TCP ports (88, 3074, 80 & 53)-(yes I have done it correctly) to allow an open NAT type, when it's moderate I do not have this problem.
The test network connections does its thing and connects straight away with no errors or warnings.
The internet connection is stable and interleaved for a better latency. I get speeds of 40mbps down and 10mbps up with a very low error rate.
The xbox is wired straight into the router. My laptop never has any connection issues, even when used witlessly so there is no problem with the router or modem.
I use a BT router with an openreach modem (both compatible with xbox/xbox live). It's a high speed exchange to cab fiber optic broadband connection.
This problem is very frustrating and I noted that other querying it have not had an adequate technical response, if it happens again I think I'll just be switching back to a moderate Nat to solve the problem. At least I wont get picked to host on WM3.
No downloading my profile didn't help.
(On a side note as a quick question that I'd like an answer to, why wont my xbox stop using the network, even when it appears to be switched off, and doesn't completely shut down until I pull the network cable? Is xbox live using the network for cloud storage and is that why when I bought a 250GB hard drive a massive portion was reserved for system space, compared to the space reserved on the 8GB hard drive? inquiring minds and all that guff....)
Please, please, please for the love of all that is holy do not recommend I look at the xbox live wizard. It's completely useless for this problem and only has very remedial information for any problem