- Is it disapproved? Merchant Center first. A disapproved product earns nothing and nobody emails you.
- Is it in stock and priced correctly? A sync problem can stop serving or trigger a mismatch.
- Did tracking break? If conversions fell off a cliff rather than sloping, suspect measurement.
- Did you change something? Change history, last 30 days.
- Did a competitor arrive? Auction insights will show a new advertiser at volume.
- Is the creative tired? Falling CTR on a previously strong asset is fatigue, not bidding.
- Is it seasonal? Compare against the same period last year, not last month.
Only after all seven should you touch bids — and then one change at a time.