A build check error in the area "manifest.json". 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
manifest.json describes the game: its slug, title, player counts, execution profile, join policy, subscriptions, smoke intents and settings. It is strict JSON with no unknown keys.
How to fix it
Fix the field the message names. Player counts are 1 to 16, subscriptions includes member.join_requested and session.start_requested, and every smoke intent's actorIndex is below minimumPlayers.
See also: every error code, the API reference and the docs.