I am..it appears that some bosses are "locked" meaning that you attempt to attack them and it says "this boss is currently being attacked by another player" However, this is occurring with every turn that you take to attack the boss. Something is locking them up. It is unlikely that the boss will be attacked straight for 5 minutes. In addition, we know that its not being attacked because the damage has not changed.
We're currently having server issues which are being worked out, game should be running as normal soon.