Hello JaLimppu
Hopefully you will see this as I saw your post was from a couple of months ago. I had the same problem and went through everything you have.
It's the printer and it's an easy fix.
Press the MENU button (right arrow) ON THE PRINTER
you will see PRINTER SETUP
Press it again and you will see the second selection down is PAPER SIZE CHECK
Select this and then select OFF
Press the center round button
Press the left arrow 3 times and print. You will see all of your glorious print spit out of the machine.
This rattled my brain for quite some time, hope it helps you.