The site is having weird outages like that. Not really for 10 mins at all but sometimes for about 3 mins it will just drop out.
Leaseweb isn't showing any attempted DDoS attacks though. My guess is that since this site is all the way in the Netherlands, it has to rely on more than others in, say, the US for the connection to stay up. Basically more things to go wrong and fewer resources to handle it with. I could be totally wrong though.