Parts of print red on Cura, doesn't work when printed

[NateA 0]

I am trying to print a relatively simple print but when I put it in to Cura parts of the print are red and when I looked at the preview of how that printing would work it showed that parts of the print would not be printed. Not sure if this is related but it also shows part of the print as hollow when I open the .stl file. I will attach the .stl, a screenshot of the print in Cura, and a screenshot from the preview tab. 

axe-6.stl

Edited May 27, 2022 by NateA

[ahoeben 1,968]

The red on the "Prepare" tab is a visualisation of what parts of the model need supports. However, this visualisation depends on the surface "normals" to be oriented the right way. In your case the normals seem to be "flipped" on some areas, which causes the red "needs support" visualisation to show up on the top of the model instead of on the bottom of the model.

 

The "Mesh Tools" plugin from the Marketplace has a function to "Repair model normals", which would normally correct this issue with your model, putting the red on the bottom of the model where it belongs. However, your model has many more issues that make it unsuitable for printing as is, and it needs to be repaired or remodelled before it can be succesfully printed. The application "3D Builder" (which comes with Windows 10) seems to do an ok job at repairing it.