Mark in - Mark out problem

Hi everyone, 

I am using the latest version of the Premiere Pro. I have never had this problem before, but now Mark in and Mark out functions don’t seem to work. I want to render a certain part of the project, so I mark in and mark out the start and the end of the video. But when I try to render it, the software renders the entire project. My selection is highlighted but it doesn’t take effect on the final result.

Anyone having a similar problem and knows how to fix it?

Thanks.