There could be a few reasons why you're getting this message when trying to register for HBTU counseling:

1. Incorrect or Invalid Input Details:

   • Double-check all your personal details, including your name, date of birth, category, and other relevant information. Ensure there are no typos or errors.
   • Verify that you're entering your NEET UG roll number correctly.
   • Make sure your contact information (email and phone number) is accurate.

2. Eligibility Criteria Not Met:

   • Even if you believe you're eligible, it's possible that your eligibility criteria might not align with the specific requirements for HBTU counseling.
   • Check the official HBTU counseling notification for detailed eligibility criteria. Pay attention to minimum marks, category-wise cutoffs, and any other specific requirements.

3. Technical Issues:

   • Sometimes, technical glitches or server errors can prevent successful registration. Try refreshing the page or attempting registration later.
   • If the issue persists, contact HBTU's counseling helpline or reach out to their admissions office directly for assistance.

4. Registration Window Closed:

   • Ensure that the registration window for HBTU counseling is still open. If it has closed, you won't be able to register as a new candidate.

Here are some additional tips:

• If you have a screenshot of the error message, it might be helpful to share it with HBTU's support team for better assistance.
• Try registering using a different device or browser to see if the issue persists.
• Contact HBTU's counseling helpline or admissions office directly for personalized guidance.

By carefully reviewing these points and taking appropriate action, you should be able to resolve the issue and successfully register for HBTU counselling.

I hope this information helps you.