Richa, please confirm twice that your login credentials, i.e. the application number and password are correct, the caps lock key is not on and they are entered correctly.

You can try going on the Forgot Password option if that doesn't help. You might get an OTP or a link to generate a new password for you.

Else you can also mail the authority on their email ID: ibsat@ibsindia.org or contact them on the toll free helpline number: 1800 425 55 66 77 with your issue and they will guide you on how to retrieve your login credentials.