Hi @eweber !
Adding to @rdoctor and your question on the browser used, I have successfully managed to download the .STEP file from the link you provided and uploaded it to a new project on SimScale from three different browsers: Chrome (Version 60.0.3112.90), Safari (Version 10.0.1) and Firefox (Version 54.0.1).
I’m currently on a macOS Sierra Version 10.12.1. and all three projects have been created and can be visualized without any problem.
Sometimes it has happened to me that while defining the mesh/simulation the orientation of the view gets messed up and the object disappears from sight, could be just an issue of resetting the view?
Have you managed to find a solution to your project visualization?