I've seen a number of people complaining of getting a "server not found" message trying to reach Mumsnet this morning - including me (I had to switch off wifi and use 4G). It seems to be Virgin Media users and has gone on for an hour or so. Interestingly, VM users cannot get to Newsthump either (I just saw it on their FB page) - problems have come up with VM not connecting to certain sites before and it seems it is them again.
The Mumsnet Towers twitter account says everything is fine and no-one else has reported a problem, but I don't think that's right. Please could you look into it again?