We’re aware of an issue affecting some customers trying to access YouTube. This is due to a recent change by YouTube that now requires users to sign into their Google account to watch videos.
What’s Happening?
YouTube has started asking people to sign in to confirm they're not a bot, especially when watching videos without being logged in. (Source: Google Support)
How to Fix It
To resolve this, simply sign into your Google account on YouTube. Once you’re signed in, videos should play as normal.
There’s no issue with your internet connection—this change has come directly from YouTube.