According to Xbox’s Larry Hryb, aka Major Nelson, there is a small update being set out to Xbox 360 users on Xbox Live today.

In this update, we are correcting some issues such as displaying the incorrect playlist name when launching a playlist from Xbox SmartGlass to the console, an error with Xbox Video closed-captioning and an error with Xbox Music that some were experiencing.

This is a mandatory update and must be downloaded if you want to connect online with Xbox Live.

Source: Major Nelson Blog – Xbox System update going out today