The blundlar app is working for you

I'd check the youtube support forums first to be honest.

mate same here untill the update it was fine but now its horible crashes evertime i watch a video say that its not working and that i should go and look at the status on xboxlive website

Thanks Daft...... support wants me to perform a factory reset on the console.

Seems you've done everything I would suggest so maybe have a look on youtube support https://productforums.google.com/forum/#!forum/youtube

no idea why that’s happening, have you tried contacting support? They may be able to help you further