This would indicate that no member of staff has a role of SENCO on the system. If, for example, your Headteacher is the SENCO but they carry out these duties via their Headteacher contract you can annotate this when uploading your census. If a member of staff has a specific contract for the SENCO roles this should be added on the staff profile.
To do this please go to Admin > Personnel > Staff - find the member of staff required. Click onto the grey cog next to contract info and add a new contract with SENCO as the role.