Error message "Cannot find category mandatory attribute" appears.

Please use either [API to search category meta data] or [Category excel file] to find the appropriate "buying option" for your category and add it to json.
This error occurs when the mandatory buying option is not included. 

*FYI
Distinguishing buying option and search option by querying meta data.  

 "attributes":       [
                 {
           "attributeTypeName": "색상",
           "dataType": "STRING",
           "basicUnit": "없음",
           "usableUnits": [],
           "required": "MANDATORY", //필수
           "groupNumber": "NONE",
           "exposed": "EXPOSED" //구매옵션
        },
                 {
           "attributeTypeName": "주얼리 사이즈",
           "dataType": "STRING",
           "basicUnit": "없음",
           "usableUnits": [],
           "required": "MANDATORY", //필수
           "groupNumber": "NONE",
           "exposed": "EXPOSED" //구매옵션
        },
                 {
           "attributeTypeName": "쥬얼리 소재",
           "dataType": "STRING",
           "basicUnit": "없음",
           "usableUnits": [],
           "required": "OPTIONAL", //비필수
           "groupNumber": "NONE",
           "exposed": "NONE" //검색옵션
        },