How to correctly use exo2nek

[theronguo]

Hello, basically I am trying to generate an unstructured hex mesh for a conjugate heat transfer problem in 3D. My aim is to use exo2gen, as it provides the tet2hex functionality. How I am trying currently proceeding is:

1. Generate a tetrahedron mesh with gmsh, extension ".msh".
2. Use meshio to convert ".msh" to ".exo".
3. Use exo2nek to generate the ".re2" file.
   Unfortunately, when using exo2nek, it fails to read the file and fails with "ERROR: cannot open file mesh3d.exo". The .msh and .exo files are attached here mesh3d.zip.

Does anyone have any suggestions on what the issue might be?

[theronguo]

I just realized that this is for nekRS, and that there is a google group for Nek5000. But perhaps someone can help me here as well?