A delivery is "Waiting on a person" (WAITING_HUMAN)

Check the delivery card and its Activity feed. The usual reasons:

• It's at a human step (merge, sign-off, human QA or review). The card says who it's waiting on. Merge the PR, or use Release / Send back. Owners get a reminder (after 1 hour by default) and later the backup is told (8 hours by default); both are set on Settings or per step.
• The step's role isn't hired (for example a Security review with no Security Engineer, or auto-routed work for a discipline you haven't hired). Hire the role, change the step, or Release it to skip ahead. The handoff note warns that nothing verified that step.
• The engineer went quiet. A step with no activity for 45 minutes is nudged; at 90 minutes it's parked here and the team is told that it went quiet. Look at what landed (PR, files), then Release or Send back.
• The engineer was at capacity too long, or kept failing and asked for help (see Inbox).
• It's waiting on a question. Answer in the thread or the Inbox.