In my tasks table it is 
And in my users table it is 
I think I know what are you hinting here to me, and I did not think to check it. It should be the same type, isn’t it? (but what about relation then?)
Edit: @david.wylie but in the example app I copied from tutorials it is the same setup I have and it works just fine. Isn’t it more of MS Access thing and its relations to be always the same type?