A build check error in the area "client/assets". An error: the game cannot be published until it is fixed.
The build check runs on every game LobbyLab builds, and each problem it finds has a stable code, the exact message, the file and line when it names one, and a link to this page.
What the check looks at
Assets are at most 100 files, 20 MB each and 60 MB in total, with simple names, at most 4 folders deep, of allowed types; .glb models embed their buffers and images.
How to fix it
Export the model again as binary glTF 2.0 (.glb).
Rename, re-export or remove the asset the message names. Prefer procedural content: the kits draw characters, props, skies, particles and sounds.
See also: every error code, the API reference and the docs.