Your task history shows all the tasks your Zaps have tried to automate. Each Zap run in your task history will have one of five statuses. Failed or unsuccessful tasks in a Zap run can be manually or automatically replayed.
Replaying a Zap only retries failed tasks, not successful tasks. 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.