Problems with my Lenovo thinkpad X1Carbon. Screen is black after I close the lid and open it back up?

So I have a Lenovo X1 Carbon, (3rd generation I think) and when I close my laptop, it sounds like its still running and if I open it up, the screen stays black but the keyboard is still on. I then have to turn the computer off and back on but it doesn't happen every time I close my laptop but it does happen often. Do you know why this happens or how to fix this problem?