Work the diagnostic in order: are records matchable → are providers returning data → are thresholds blocking fills → is the cascade configured for this segment. The fill-rate report pinpoints the stage.
Step 1 — Matchability
Records need at least an email or a company domain to be enriched. Check the "unmatchable" count in the fill report. High unmatchable = fix data capture upstream, not enrichment.
Step 2 — Provider returns
Check the per-provider return rate for the affected field. If all providers return near-zero for a segment, it's a genuine coverage gap — you need a different provider, not different settings.
Step 3 — Threshold blocks
The "filled below threshold" share tells you if quality gates are eating your fills. Sample the blocked values; if they look right, lower the threshold one step and re-run.
Step 4 — Cascade scoping
Check segment rules — a rule limiting premium providers to A-tier accounts will show as low fill on B/C-tier. That may be working as designed, or you can widen the rule if the data justifies it.