Seems once I created the user in stapp02 and click check button is not validating the user creation.
Note that the task is: “[c]reate a user with non-interactive shell for your organization on a specific server. This is essential for service accounts and automated processes that don’t require interactive login capabilities.”
The operative word here is “non-interactive”. Since /bin/bash is an interactive shell, you’re setting up the user wrong 
Instead, you need to do something like
sudo useradd -m -s /usr/sbin/nologin user-name