A specific source of inventory generates less impressions than preferred (but more than 0).
Verify the following:
- Verify that expected bid request volumes of the source are received in Supply
- Verify that targeted audiences, filters or geo targets are not potentially decreasing eligible volumes
- Use target share (%) to increase the bid rate of the inventory source's bid strategy. If several strategies and inventory sources are targeted, each strategy will receive impressions proportional to its share of the total.