I seriously doubt you are "blacklisted" or anything similar. You've only failed 3 final round interviews, which doesn't strike me as an uncommonly large number.

I seriously doubt you are "blacklisted" or anything similar. You've only failed 3 final round interviews, which doesn't strike me as an uncommonly large number. Can you elaborate on whether it is technical or behavioral rounds that you seem to be failing? It might simply be a personality thing with the few places you've talked to. If you are interested, I am willing to give you a short mock interview and provide you with objective and honest feedback to see if we can figure out what is going on. Feel free to get in touch, contact info is my user profile.