Resolve STEP/DXF File Errors for Metal Sign

Hi, I need urgent help fixing a CAD file for production of a folded metal sign. The supplier’s software rejects the file with Error 3007. According to the supplier, the model is not built correctly for manufacturing... (Budget: $10 - $30 USD, Jobs: 3D CAD, 3D Design, AutoCAD, CAD/CAM, Fusion 360, Manufacturing Design, Mechanical Engineering, Solidworks)