The Excel file contains a sheet name "Main", but in the Excel schema definition it is displayed with value (1??). Further, the value cannot be set correctly from a drop down list, as the right value is not present in the list. The name displays correctly after uploading the schema, but displays as (1??) when the schema defined previously is opened.
When we set the sheet name in Excel schema, it is encrypted after saving the schema. The above situation occurs when the sheet name in the schema definition is manually edited, and the schema is saved and reopened. We suggest that you do not manually edit or change the sheet name in the Excel schema definition.