I turn on my Xbox 360, I sign in and it connects to Xbox Live. I try to boot a game up (in this case it's dark souls), and I get signed out of xbox live. Why is it doing this? I can't sign back in while the game is open, and if I try it will take forever to sign in, I waited 3 hours and it was still signing in. Please help!
This is a known issue in the world of Xbox live and a simple "wipe" of your account should do the trick. After you've redownloaded your Account, the problem should be solved.
There is a thread in the Xbox-Forum where people tried to collect several solutions. I hope this can help in your case.
Here is a simple instruction:
Step 1: Run the Live Connection Test
Usually the test will go through as normal but just to be sure, check the results in case there are any error codes or messages. In some cases, running the test alone can sort things!
Step 2: Clear the Console Cache
Don’t worry if you’ve never done this before; clearing the cache on the console won’t remove a Gamertag, DLC, game saves, or any dashboard updates. It will clear out some temporary files and game “title updates.” Those are the updates that get downloaded when a game starts up.
To clear the cache:
Go to the Storage Menu
Press ‘Y’ on a storage device (not the cloud)
Select “Clear System Cache”
Confirm with “Yes”
That’s it! It only takes a second or two for the cache to clear. If your Helpee thinks nothing happened, they may have just blinked and missed it!
Step 3: Re-download Profile
Next, the helpee’s profile needs to be downloaded to the console again. To avoid even the possibility of losing something important, only recommend they download the profile. Do not recommend deleting the profile! Downloading a profile is done by going to the Sign In or Out Screen and going all the way to the right. Once the MSA and password (or two-factor code) is entered, the download will start.
Step 4: Restart the Console
This is another safety step. Err on the side of caution and give the console a little downtime.
That should stabilize your helpee’s connection to Live! If any error codes or other hurdles show up during these steps, switch gears and work to resolve those before going on. Prepare to help with getting passwords remembered and security proofs set!
The quoted instruction can be found here.