Node access user refference module doesn't work for some reason. What I did wrong?

Hello there!
Can somebody help me please, with this very usefull module?! What I did not correct?
I enabled this nodule and added the field user refference in my content type and select the permission for users (delete, update, etc).
Then I added a user in the content via the field user refference.
But that user can not edite or delete that content.
Should I set up something else?
Thank you for any help!