It's really weird because usually the .htaccess file does not introduce any problems if nobody changes it. It may be actually a sign that someone is doing something on the server. Let's hope the changes will turn out to be good.
On the Moho Animators' Facebook page yesterday, Michi Catanese (who works/ed) for Moho posted: "It is not gone. I've notified the person who runs it. He is out of town and will look into it as soon as he can." So hopefully it will be back up sometime fairly soon.