I can’t launch the game using HD.

I changed my internet provider. And now, believe it or not, I have the same problem. Apparently, there's a lot we don't know about HD mode ;) The connection in World of Tanks is fine, but now I can't play on Heroes of Might and Magic... The conclusion is that this is the work of dirty World of Tanks players :D
But seriously, this is a very sad problem...
I'm continuing to look for a solution.