Hi @Prayas_Arora thanks for submitting a question!
First of all, your query DSL looks reasonable, but if you're using Elastic v5.x that is a very old version that is well past end of life. I'd strongly suggest considering upgrading if you can.
With that said, it sounds like people have run into this before on 5.6, and you may have to use plugins. See this previous post for more information.
Good luck!