This query will show if you have recorded zero in the free school meals taken area (Admin > Census > Spring 2020 > Free School Meals) and have students who are recorded as being eligible for free school meals.
To update this click free school meals in the spring 2020 census specific data table with the census area. Enter the number of free school meals taken on census day and click update.
To check who is eligible for free school meals you can do this in Reporting > Reports > Students Tab > Free School Meals.
If this is correct and no students took a free school meal on census day you can add an explanation on collect when uploading the census.