Hello Sofeiyakalaimathy Covindane,
Thank you for posting your query in the Microsoft Q&A forum. Please be informed that when you activate your subscription, it is assigned to the home tenant of the user (The home tenant being the tenant where the user is created). This is the reason why you are getting the error "Need to use work or school email".
To resolve this, kindly create a user in your tenant (either in Azure or M365), assign a role to this user (preferably a Global Admin role), and use this user to activate the license.
Do let me know if further assistance is needed.
Babafemi