We apologize for the delay. We ran into some unexpected difficulty during the maintenance. We are working as hard as we can.
We still need several hours to take care of the situation. Thank you for the patience.
Update (14:10 CEST): The issue with maintenance is still being looked into. Unfortunately, we have no ETA to give at this moment. Your patience is appreciated!
Update 16:00 CEST - The Hearthstone maintenance has been completed and the patch should now be active in the EU. Sorry for any inconvenience this delay caused.