This error indicates that a data match has been encountered for that student. This means that the student may already have a USI and you will need to confirm this with the student.
If the student doesn‘t have a USI, there could be a duplication or another person in the system with similar details. In this case, ask the student to create the USI. If the same problem occurs, they will be able to submit a help request in the USI System when the Help Request link appears.