Journey Builder Zero Injection — Advanced Triage
When a Journey is Running but the contacts you expected never enter, separate source population, event evaluation, identity and re-entry behavior.
Evidence tier describes my hands-on relationship with the content. Official sources describe platform contracts/documentation. Production observations should not automatically be treated as official limits.
Prove the source contains eligible rows
Inspect the exact Entry DE/API payload at the time the event evaluates. Do not rely on a later snapshot.
Confirm event mechanism
Scheduled DE, Automation/Fire Event and API Event have different execution paths. Verify the one actually connected to this Journey version.
Inspect entry/re-entry settings
A matching row can still be rejected by No Re-entry / Re-entry After Exit or entry filter logic.
Validate ContactKey mapping
The Entry DE sendable relationship controls ContactKey/SubscriberKey resolution. Confirm identity consistency.
Review update action semantics
When Automation Studio writes the Entry DE, Overwrite versus Add/Update can change what Journey Builder sees as already evaluated.
Check rejected/history evidence
Use Journey History/entry results where available to distinguish “not evaluated”, “rejected”, and “entered then exited”.
Test one known contact end-to-end
Use one deliberately controlled row and record source value, ContactKey, evaluation time and resulting Journey behavior.