You probably have the survey set up to only allow each password to be used once. If you try to use the password again, you would see this "No additional interviewing" message. If you are in field and a respondent is seeing this message, check to ensure that a password has not been assigned to more than one respondent. (Perhaps a previous respondent has already taken the survey.) If you are certain that this respondent has not entered the survey, or perhaps was disqualified based on a faulty answer, you can delete the old record, renumber the old record, reissue this respondent a new password, or modify the password to allow more than one entry.
If none of these seem to be possibilities or just don't seem to address your situation, contact our technical support team for personalized help on your specific situation.