Solution 1: Restart your Xbox 360 console.
Solution 2: Check the password of your Microsoft account. Make sure the specified password is correct. If you forget your password or can not log in with your password, reset the password.
Solution 3: Try to log into Xbox.com. This is how:
Click Login at the top of any page on xbox.com, like this.
Enter the username and password of your Microsoft account, and then click Login.
If you can log into Xbox.com, try to log back into your Xbox.
Solution 4: Update Microsoft Security account. Check and, if necessary, add safety information to your Microsoft account. For example, add a new email address or telephone number.
For information about how to manage their Microsoft account security, see Get help with your security information Microsoft account.
After checking and updating information up your Microsoft account, sign in to Xbox Live and try to purchase or download the content again.
Solution 5: Clear the system cache memory. This is how:
Press the Guide button on the controller.
Go to Settings and select System Settings.
Select Storage or Memory.
Highlight any storage device, and then press Y on your controller. (No matter which storage device choose: all cache memory storage devices are erased).
Select Clear System Cache.
When prompted to confirm storage device maintenance, select Yes.