Determine if you are using the wrong transform map
Field maps establish a relationship between a field in an import set table and a field in the target table. The field map determines what values from the source table the transformation adds to the target table. If you are having trouble with a CI, it could be that you are using the wrong transform map and need to select the correct one. For more information on transform maps, see Create a Transform Map in the ServiceNow product documentation.
If you are an administrator, you can look into the Import Logs and Import Set Row Errors to see if the data import successfully finished and if there were any import errors. The Run Import utility is used to run an import operation using an existing transform map and import set table. For more more information, see Import Logs in the ServiceNow product documentation.