Your Zap history shows all the tasks your Zaps have tried to automate. Each Zap run in your Zap history will have one of five statuses. Failed or unsuccessful Zap runs can be manually or automatically replayed.
Replaying a Zap run only retries failed steps, not successful steps. For example, a Zap might have two actions: 1. Send an email and 2. Add a spreadsheet row. If the Zap runs and successfully sends the email, but fails to add the spreadsheet row, replaying the Zap run will only attempt to add the spreadsheet row again, not send the email again.