To active Astra Website Protection as part of your GitHub Student Developer pack, you need to make sure that:
You are enrolled with the GitHub Student Developer Pack
Your email id in your GitHub account is verified, and public
Step 1 - Uncheck "Keep my email address private"
Login to your GitHub account, and navigate to Emails in the Personal settings section
Enter a verified email in the Primary email address field
Make sure that Keep my email private is unchecked
Step 2 - Display verified email
Login to your GitHub account, and navigate to Profile in the Personal settings section
In the Public Email section, choose Select a verified email to display