As a leader, confidence is necessary. There should also be real knowledge and experience behind it, not a false air or façade. But there are times when a decision, in hindsight, was clearly wrong.
When this happens, you have a choice to acknowledge the mistake, or completely ignore it. To never bring up what happened with your team may be fine, but as it happens more over time it will appear as ignorance.
The other option is to acknowledge the mistake, realize what should have been done, and admit this to the team. This kind of transparency makes a leader easy to follow and helps build trust. Mistakes will happen, don't sweep them all under the rug.