VM are aware of the issue. The same error message and code is displayed in the app that was there yesterday. "Not available. Sorry-we can't play this at the moment 4001"
It's actually working on my Windows 11 PC, but not on my android tablets or mobiles (I don't have any ios devices to check).
It doesn't look too good for a solution for the app though with it being Xmas Eve, and sadly as you are already aware MTV Live, along with MTV Music, MTV 80's, MTV 90's, and Club MTV are closing on all platforms in the UK and globally on 31st December 2025, as part of Paramount's shift from traditional TV to digital content.