According to the issues list, a few meshes had "Normals issues". I believe the rest of the list is for missing textures.
I don't suppose the latter is an actual issue, as one can upload them later, manually.
I did recalculate the normals in Blender for the mentioned meshes, but these meshes still appear in the Error list for the same problem.
If the normals is not the reason why it fails to process it to load it when uploading, then I have no idea what it could be.