There was an outage on YouTube https://downdetector.co.uk/status/youtube/ and at the time of making this post the information was correct, however the current version of the Chrome browser (W10) is 86.0.4240.198 (Official Build) (64-bit). See if there is an update for your app.
I'd certainly suggest you call Virgin to report the issue, but if your box's internet connection is working (which it is if your VOD works), VM may be limited in what they can do, if it's YT's app that isn't working - you may also have to report it to YT.
As a general thing, if you use the streaming apps a lot, you've had your package a while, and also have VM broadband, you may want to consider looking at your package with a view to swapping to the V6 box. Much newer and a lot better at streaming apps in general.
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