curl --request GET \
  --url https://api.hubapi.com/crm/v3/imports/{importId}/errors \
  --header 'Authorization: Bearer <token>'

{
  "paging": {
    "next": {
      "link": "",
      "after": ""
    }
  },
  "results": [
    {
      "createdAt": 123,
      "extraContext": "<string>",
      "objectTypeId": "<string>",
      "errorType": "INCORRECT_NUMBER_OF_COLUMNS",
      "invalidPropertyValue": {
        "sourceId": "",
        "selectedByUser": false,
        "sourceLabel": "",
        "source": "",
        "updatedByUserId": 123,
        "persistenceTimestamp": 123,
        "sourceMetadata": "",
        "dataSensitivity": "",
        "sourceVid": "",
        "unit": "",
        "requestId": "",
        "isEncrypted": false,
        "name": "",
        "useTimestampAsPersistenceTimestamp": true,
        "value": "",
        "selectedByUserTimestamp": 123,
        "timestamp": 123,
        "isLargeValue": true
      },
      "errorMessage": "<string>",
      "knownColumnNumber": 123,
      "invalidValueToDisplay": "<string>",
      "id": "<string>",
      "sourceData": {
        "rowData": [
          "<string>"
        ],
        "containsEncryptedProperties": true,
        "lineNumber": 123,
        "pageName": "<string>",
        "fileId": 123
      },
      "objectType": "CONTACT",
      "invalidValue": "<string>"
    }
  ]
}