Is it really "maintenance", or is it another deliberate problem created by yet another selfish, spiteful troll? It says try again in the next hour, but it's been like that for about a week now. Why do you think that is?
No, you don't have the right to copy things for personal use unless it's granted by the owner.
Copyright laws are so strict that automakers actually copyrighted the software used in cars and made it illegal for anyone else to access or update the files. It was huge news in the auto industry when the laws were rewritten to allow people to take their cars wherever they wanted and the mechanics could fix issues if they weren't part of the maker's company. Until then, people owned their cars, but they couldn't touch the software.
There are allowances made in general under the fair use guidelines that allow things to be shared for educational or journalistic purposes, but only parts.
Heck, I played Simon and Garfunkel's Red Rubber Ball in the background of my tutorial on how to embed videos on answerMug. It got nixed in some countries for violating copyright... and rightly so. I was ok under American laws, as far as I can tell. I had maybe 30-45 seconds of the song and it was used in an educational way, but yeah, shame on me. I didn't even think about it.
They scan everything as it goes in. Odds are, if you even share a video with a pic of you and Mickey Mouse in it, it'll get pulled by YouTube for copyright. It's that serious.