Every seller the agent turns down finds out why.
Pick a brief and run the agent. It compares the offers, picks one, and tells every other seller why it passed.
Where the reasons come from: a buying agent already knows what its user wants, from what they asked for and from what they've chosen before. Always free cancellation, only live football, never a yearly contract. When an offer misses one of those, that's the reason the seller gets. The agent here only has the brief.
What do CTV, CPM and DV/IAS mean?
CTV is Connected TV: ads shown in streaming apps watched on a TV, like the ad breaks on ITVX or Channel 4's streaming service. CPM is cost per thousand: what an advertiser pays for every 1,000 times the ad is shown. A £30 CPM means £30 per 1,000 views. DV and IAS are independent companies that check ads ran where and to whom the seller said. Format and price limits are usually filtered before an offer reaches the agent, so the reasons here are the judgement calls.