Separate time waiting to send from time waiting for delivery. Connection recovery, campaign pacing, funding, and safety limits can delay a send; an accepted message still needs a later delivery result. A healthy number does not guarantee instant delivery.
Compare request, send, and delivery timestamps for a small sample. Check the campaign or message's actual pending reason. Do not increase concurrency or repeatedly resend to clear an unexplained delay. If the delay persists, give support the references, time range, and sender status so the correct stage can be investigated.