Ad source diagnosis
One ad source stopped filling: what should you check?
A weak source-level fill or match rate does not automatically mean the whole app cannot serve ads. In bidding and waterfall setups, another source may win, fill, or take most of the eligible volume.
Start at the app and ad-unit level
Check whether app-level requests, fills, impressions, show rate, and revenue actually changed. A source-level decline matters most when it changes total serving or revenue contribution.
Read source metrics in context
Compare bids, eligible responses, fills, wins, impressions, revenue share, and eCPM where the platform exposes them. Low source-level volume can be normal when other sources win.
Verify serving conditions
Check source status, SDK or adapter initialization, consent, placement mapping, floors, geo availability, and recent changes to the mediation configuration.
Source-level checks
- Confirm whether app-level fill, impressions, or revenue also declined.
- Compare the source by country, placement, ad unit, format, and app version.
- Review bids, fills, wins, impressions, revenue share, and eCPM where available.
- Check source status, adapter versions, initialization, consent, and placement mapping.
- Review floor rules and mediation changes near the movement.
- Do not remove a source only because one platform-specific rate is low.
How to read it
Common interpretation
If app-level serving remains healthy while one bidder loses volume, auction competition or source demand may have shifted. If total fill and revenue fall with that source, its configuration or availability becomes more important to investigate.