Hi @Giuseppe272738705as7! This is a known bug and the engineers are currently investigating. It might take some time for them to figure out what had happened.
A workaround solution is to make sure the ground plane is enabled when rendering.
We are not able to diagnose working files directly on the forum website. Can you email the Stager log file from the scene you're trying to render to Substance3d-bugs@adobe.com. If the file is under 20 MB you can attach it directly to the email. If it's larger, you can send via a file transfer link like Creative Cloud assets, Dropbox, We Share, One Drive, Google Drive, or similar.