Just started using the site today, so hopefully this isn't the case.  Although I have to admit this error specifically is somewhat discerning as most sites have some sort of notification for maintenance or DDOS or the like.  Would be a shame, as the site has a nice layout and is quite easy to use.  If it comes up I'll probably pull my balance manually to my wallet just in case it is maintenance related I'll still be able to access my funds during the downtime.

Update:  Posted on twitter asking about the downtime, still awaiting a response.  Will check back if/when I receive a response.

Update 2:  Can't find an official update anywhere.  The iRC channel #bytecoin-dev on Freenode has 5 people in it, none of which seem to be officials from HitBTC, and none of which will respond.  The twitter post still has no response.  These forums have no response.  Starting to get worried.  I guess it's a good thing I always do micro-transactions for the first few trades on new exchanges, I could have just saved myself a huge loss.