Scriptables is designed to build servers systematically, incrementally executing tasks - step by step. When something fails, Scriptables - will stop the build and report an error in the logs.
On failures - the above icon will appear under actions to allow you to retry the build. Clicking this icon - will automatically retry from the last failed step, and continue building until all steps are completed or something fails.
Next to the server's name, as you will see above there's a "green tick", indicating that this server build was successful. Other status icons are as follows:
Failed, queued to start, and the build is running respectively.