Hi, I'm also new here =)

Have a had my MiniKossel for two years now and just the other day got the same problem when I recalibrated. Not that much but 0.2-0.3 mm. I had to increase the "diagonal smooth rod value" 1 mm to get the print head down. I don't know what the value represents. Default is 145 mm and I cannot figure out what it refer to. Some kind of radius maybe. If you haven't got it right yet I suggest you play around with the value and make bigger changes to see what happens. Good luck!