Why are GA4 Measurement Protocol events visible in DebugView but missing from reports?

Usually GA4 received the hit, but it either hasn’t reached the report you’re checking yet or you’ve told GA4 to exclude debug traffic. DebugView is live troubleshooting data; regular reports can take 24–48 hours to settle. If the payload has `debug_mode`, an active Developer traffic exclude filter deliberately keeps it out of reports while still letting you use DebugView, so check Admin → Data filters first. Also, don’t treat a 2xx from `/mp/collect` as proof the event was accepted: Google says it can return 2xx even for malformed or unprocessed payloads. Run the same request through `/debug/mp/collect` (or Event Builder), then check the identifier, event name, and parameter limits. If you expect session or Realtime context, include a current `session_id` and sensible `engagement_time_msec` too.