Wasted 14 hours of my time today grinding out a new Seasonal HC just to die to a server connection time out, rather disappointing . Should figure a way to distinguish a HC death from a error on blizz servers vs players ISP because this is just plain stupid , was looking forward to pushing top of leader board , not going to happen now.
The US servers are not crashing once an hour. Are you playing from ANZ? If so please see this thread. It contains a way to force your game to connect to the US servers, which would have a slower connection, but be more stable.