Hi @Radha Rajendran ,
There are a number of things that can cause this error. Please make sure you have entered the correct TenantID, ApplicationID and Application_Secret, and the Group name in the application.properties file under src/main/resources
I would also check some of the solutions in these related threads:
Access Token Response Unauthorized
Unable to Authenticate Using Spring Boot Sample
Invalid Token Response
Token is not Authorized immediately
If you still have this issue, please provide any trace logs you may have, along with a screenshot of the API permissions that you have added.