Its really hard to say without knowing you in person and there are so many factors that could effect this I can only really make guesses as to why you are being

Its really hard to say without knowing you in person and there are so many factors that could effect this I can only really make guesses as to why you are being rejected. Are you applying to junior roles? If not then maybe you are punching above your weight. Also, and this might not be easy to think about, but could it be a personality problem? Perhaps you came off as arrogant or somebody who would be hard to work with? In the interviews you've had were there any questions you were asked that you couldn't answer or that you stumbled on? What were those questions? Also I would try hard to ask the companies who rejected you, why they rejected you. Of course they will probably say something like "we didn't feel you were the right fit for our team" but try and push them to give you legitimate feedback. Tell them you are genuinely trying to figure out why you are not having success in interviews and hopefully they will be kind enough to give you some constructive feedback. That said I'm not 100% sure this will work but its worth a try.