Issue got resolved. I have upgraded during night. So I left the server idle over night (around 6hrs). Now it works fine. It could be sync issue. Some times it takes lot of time. So far I have experienced 3.0 is super slow. I heard from Qlik support that, they have loading & sync issue in 3.0.0, so they are releasing 3.0.1 in 2 weeks with these 2 fixes.