I can log in to the CP. I don't know why. I just played like an hour ago. I DC'ed now, i can't connect to the server. Weird much? I tried reinstalling using the HeRO mini installer but to no avail.
Ya, if you get 'Failed to connect to server' again and again, it means server was down or network connection problem. For that you need not to re-install HeRO rather than you should wait.