Error Message When Trying to Import a Vest Mesh

Hello, recently I completed editing a vest mesh in Blender (version 2.78 on my Mac), saved it as a .blender file, and tried to import it into the Sims 4 Studio as a mesh for the original vest (1.3.1.5, Apple Blossom). Here was the error message that popped up upon the failed import:

Sims 4 Studio 1.3.1.5 (Apple Blossom)
S4Studio.Blender.Sims4StudioBlenderException: Exception of type 'S4Studio.Blender.Sims4StudioBlenderException' was thrown.
at S4Studio.Blender.BlenderUtilities.RunBlender (System.String script, System.String blend, System.Boolean background, System.Boolean check_version) [0x002c3] in /Users/a/thes4studio/TheS4Studio/S4Studio.Shared/BlenderUtilities.cs:232
at S4Studio.Blender.BlenderUtilities.ImportGeom (System.String custom_blend, System.String custom_geom, System.Int32 body_type, System.String cut) [0x00
099] in /Users/a/thes4studio/TheS4Studio/S4Studio.Shared/BlenderUtilities.cs:361
at S4Studio.ViewModels.CAS.CASLODItem.ImportMesh (S4Studio.Blender.BlenderUtilities blender_util, System.String blender_path) [0x0014b] in /Users/a/thes4studio/TheS4Studio/S4Studio.Shared/ViewModels/CAS/CASLODItem.cs:194
at S4Studio.ViewModels.CAS.CASStandalone+<>c__DisplayClass71_0.<ExecuteImportMesh>b__0 () [0x0000d] in /Users/a/thes4studio/TheS4Studio/S4Studio.Shared/ViewModels/CAS/CASStandalone.cs:427
at S4S.UI.Core.S4SWindow+<>c__DisplayClass11_0.<BeginLoading>b__1 () [0x00016] in /Users/a/thes4studio/TheS4Studio/S4Studio.Mac/UI/Core/S4SWindow.cs:171


Here is the vest I edited - I'm very new to this, so it's entirely possible I messed something up while editing it and it clashed with the program: mega.nz/folder/jMVmQaQa. (The file labeled "Marty vest 2" is the .blend file I was trying to import. The file labeled "Marty vest 3 - ORIGINAL" is the original vest before I edited it. It it also what I was trying to import the previous mesh to, in the Sims 4 Studio).