So I know there's several discussion about this but I'm not able to find the exact answer. I was in Drublog Chieftain tower killing a boss with a NB/DK team, neither him or I could interrupt the boss regening health, we eventually out dps'd him to death but man that took awhile. So I tried my "venom Arrow" and got the "the enemy is too strong message" then I tried the traditional "Block tap LMB" and nothing, the DK tried "Shield Bash" repeatedly and nudda.
So what do you do to interrupt enemies who are "To Strong" for your interrupt skills to work??