Hi, thanks for reaching out. If you're getting the "email not registered" message, please double-check that you're using the same email ID you used while registering for the course on the NPTEL portal. Also, make sure you have successfully enrolled in the course and submitted the exam form. If everything seems correct and it's still not working, please send us your registered email ID, course name, and a screenshot of the error, so we can help you further.