Most likely related to this message CGT sent some time ago:
"We have recently updated our content policy regarding 3D printable models of guns. These changes have been implemented to address societal concerns and regulatory changes.
CGTrader is no longer permitting 3D printable models which are replicas or realistic depictions of guns or other firearms on our marketplace.
We have reviewed all 3D assets and have suspended those matching this criteria. Please keep this content policy change in mind when you upload new 3D assets to your portfolio on CGTrader.
If any of your 3D models of guns affected by this update can be used for other purposes in addition to 3D printing, please remove all 3D printing file formats from the 3D models’ archive and reupload them. "