It might be that you haven’t completed the necessary National Insurance fields when the FPS was submitted. Please see the information under the ‘National Insurance’ heading in the attached link which explains what payroll information you need to report to HMRC.
If you have already included this information then you should contact your software provider.
However, if you are using HMRC Basic PAYE Tools to make your payroll submissions then you should contact our Employer Helpline on 0300 200 3200 to discuss this issue. The helpline is open Monday to Friday 8am-8pm and Saturdays 8am-4pm.