First, make sure the user's account is not currently locked. Go to the Users page (within the Manager menu) and locate the existing account. If the Enabled box is unchecked, edit, check the box and save.
Then, have the user go to the login page (https://app.5starstudents.com/login) and follow the "Forgot your password" link. They can enter their email address and receive instructions to reset their password.
If the user is trying to use a different email address, you will need to send them a new account invitation.
For further assistance, please contact us directly at firstname.lastname@example.org