You make your Job to fail if any task fails - tick the box on the user interface on Fail Job if any Task fails!.
Alternatively you can use conditions in your Job.
You make your auth script to exit 0 if auth is successful and exit with 1 if not or cancelled or timeout perphaps...
Then in your Initial Deployment Job go to New / Condition - depending on exit code from your script task adjust further actions.
Should look something like this below: