This error can be attributed to many factors, But is mostly due to issues with the game regonizing your Xbox Live Gold subscription.
Keep this in mind, To play Perfect Dark Zero and Perfect Dark XBLA online, you need an Xbox Live Gold Subscription. We reccomend, assuming you are on Xbox One and above, getting a Ultimate Game Pass subscription. Not only do you get Xbox Live Gold, you also get Perfect Dark Zero, Perfect Dark, and Goldeneye 007 for free.
Enough of that, Lets get to it.
Most commonly, after youve purchased Xbox Live, Perfect Dark Zero may take some time to recognize that you can connect to their servers. The easiest way to make this happen spontaneously is to Redownload your Xbox Live profile via the 360 menus.
Open the Xbox 360 menu by pressing the "Start" and "Select" Icons located on your controller, you can find them by the xbox home button.
If your not already signed out, press the X button to sign out of your account. This will lead you to a menu with the option to download a profile.
Select "Download Profile" From the Xbox 360 menu. this will prompt you to a screen where you will have to select "Download Profile" Again.
Finally, you will have to enter in the information associated with the Xbox account you would like to sign in with. From here, your all set! You should be able to play online now.
Assuming you are over 18 years old, you probably don't have parental settings enabled on your Xbox profile. If you are under 18, please consult your parent first about allowing you to play an online game. If your over 18, this is how you disable these settings, in the case that youve accidentally enabled them.
Didn't work? Try resetting your Xbox by signing out, turning it off, unplugging it from the wall, plugging it back up and signing in again. If its still not working, email us at email@example.com with screenshots/pictures of the problem, and a discription of what went wrong, and we'll help you!