Mythos one victoria arduino grinder jammed


I recently got a second hand mythos grinder. It’s in a really bad state so I took it apart to clean the whole machine from top to bottom. However, now I’ve put it back together it doesn’t grind anything (but it definitely was before as I tested it). I think the back burr is jammed as I got it off originally to clean but now it won’t come off at all. I’ve tried everything to get it off and tried jamming something from the clumb crusher mechanism but still it won’t release.

Has anyone had this happen to them and know how to release it?

Thanks so much.