@Saravana To sign up for a session go back to the overview of this course and select trainings or search for Developer Certification Live Prep Session under All Events on your homepage or in the Schedulo app.

Try below link:
https://academy.unqork.com/web/en/app/schedulo/view-trainings?action=requestTrainings&courseid=lex_auth_014105176336539648370

I am able to register:

Hi Saravana. For any questions regarding training, please reach out to support.unqork.com.