Greetings
Four20Fisher! Thank you for posting about this issue on the forums, and many warm welcomes. Which Assassin's Creed game are you having this error with on your Xbox One? While this thread is specifically for Assassin's Creed Valhalla, I'll be happy to move this post over to the best location once I know which title we're working with.
To answer your questions, this error can be caused by a multitude of factors but they all mean that there is an issue between our online services and yours. Once I have a better understanding of the issue at hand, I'll be happy to troubleshoot this error further with you, so you can get back to playing the game.