Campaigns that are running and spending, but cannot serve part of the inventory they are entitled to because the file does not exist. Nothing in the platform reports this: the campaign looks healthy, it is just absent from placements it could be in. Each line is closed by producing the asset at the size given. Text is counted the same way: a rotation slot Google will serve, with nothing written in it. Only work the studio has to deliver is counted, so an asset Google generated for itself leaves the slot open.
Meta is not connected yet, so this page reads Google only. Meta ads are checked here once the Meta access token is set.