HR not accepting to reduce the Notice period from 60 days

So as per my company policy my current notice period is 60 days.

I currently got an offer with 110% hike but the catch is i have to join the company immediately. So i spoke with my manager and mailed my resignation, he accepted and approved for letting me go in 2 weeks with a buyout, but my HR is not accepting to let me go in 2 weeks they are saying i have to serve a minimum of 30 days.

So what are options there for me to get relieved from my company in 2 weeks. Can the HR block reliving even after the manager has approved it.