What happens when a post doesn't go out?
If the network turns a post away for a passing reason, Herrald tries again a few times, waiting longer each time. Before each new try it checks whether the post went out after all, so a post is never put up twice.
If it still doesn't go, the post shows Failed with the network's reason, and the people who publish for that brand get an email. Press Retry, or post it yourself and press Mark posted.
A post on a paused or disconnected channel fails with the reason, so nothing goes out where you stopped it.