Upvotes on comments, or on submissions? How do you know they don't count? What tests have you done? With no more information than just "my votes don't work" it's like a user saying "the internet is broken."

HN has lots of features to help protect itself against spam, sock puppets, voting rings, and more. Maybe you inadvertently tripped something, maybe you've fallen foul of some detector, but there's no chance of working it out when all you say is "It's broken."