When a delivery fails, QStash schedules the next attempt according to the message's retry delay. This endpoint skips the remaining wait and delivers the message right away.
Retrying now does not add an extra attempt. It moves the already scheduled retry forward, so the retry count and the remaining retries stay the same.
You can find messages waiting for a retry by listing the logs with state=RETRY.
See Retry a Message Now for more details.
Note
Messages published to a queue can not be rescheduled to retry now. The request returns 400 for them.