When Facebook CAPI Events Disappear: How to Debug Server-Side Tracking
Facebook CAPI events can fire successfully in GTM preview mode yet never reach Meta—and most store owners have no way to know. The debugging gap is architectural: preview mode confirms the tag fired but cannot confirm Meta accepted it. Response codes (200 success, 400 rejection) require paid server-side log tiers with per-tag activation. Events Manager shows aggregate diagnostics—you see “event issues” but not which specific events failed. Missing Event ID parameters cause 80% of deduplication errors. Event Match Quality scores of 4/10 are typical when sending minimal user parameters. The solution is visibility at the event level: see every delivery status, every response code, every error before problems compound into campaign performance collapse.