If you are unable to log in to the new generation e-ticketing system of IRCTC (Indian Railway Catering and Tourism Corporation) even though you are registered in the old system, you can try the following steps:

1. Ensure that you are using the correct login credentials such as your username and password. If you are not sure about your username or password, you can try recovering them by clicking on the “Forgot Username” or “Forgot Password” options on the login page.
2. If you have already tried recovering your login credentials and still can’t log in, you can try clearing your browser cache and cookies and then attempt to log in again.
3. If clearing your browser cache and cookies does not resolve the issue, you can try accessing the IRCTC website using a different web browser or device.
4. If none of the above steps work, you can contact the IRCTC customer support for further assistance. You can contact them through their customer care number, email, or social media channels.

I hope this helps!