IntelliJ, Alt+Enter doesnt work

Question

When working with IntelliJ on a JavaProject it shows to use alt + enter to import a class for example, but this isnt working anymore.

It worked in the past, but some

Answer 1

In my case, I mapped Alt+Enter to a system shortcut (for expanding the current window) and I forgot. So it might not be another program, but your past self-sabotaging you.