Can somebody help please I'm losing my mind!

I'm trying to design a box, a jewellery box to be precise and I'm having a lot of trouble with the top piece (lid) The model seems okay, I drag the stl into cura, looks fine still, then when I slice, part of the hinge piece is missing. The bottom didn't have this issue and both bottom and top pieces are identical other than where the hinge is. I'm using Sketchup to model this and I feel like I've tried everything, I can't get it to work. I've included the stl file to have a look at. If it makes any difference I'm using Sketchup web app and Elegoo Cura 4.8.0

I have since found a work around for this, if anyone else has this problem.

I separated the box lid from the hinge piece, saved them both as separate projects, then I imported them both as components into a new project, put them back together and grouped it all, seems to work but Sketchup isn't the most consistent program so it might not work next time.

From comments I've seen on this forum, Sketchup is a poor choice for producing STL files.

Plenty of free cad programs on the internet that work well for producing suitable printable files for 3D printing. Fusion 360 is very good but has perhaps a steeper learning curve than others.

Look on Youtube for the various programs available.

Thank you for your reply.

I am aware Sketchup wasn't designed with 3D printing in mind, that said it does claim to be compatible. I've had a couple issues before, I just really like how Sketchup works, I've been using it since I was at school. However I will take your advise and have a look for alternatives.

onshape.com is fully functional software and is free but your models are open to anyone with an account.. If you pay a fee your stuff is private.