DynamoDB getItem PHP问题

不确定,从DynamoDB获取项目时出现了什么问题。

Json-数据视图:

{
 "section_id": "6177d23bb5f04ca363fe3d91",
 "chapter_id": "6177ccd4b5f04ca363fe3d63",
 "data": {
 }
}

PHP代码:

    $sdk = $this->sdk();
    $dynamodb = $sdk->createDynamoDb();

    $result = $dynamodb->getItem(
        array(
            'TableName' => 'sections',
            'Key'   => array(
                'section_id'   => array(
                    'S' => '6177d23bb5f04ca363fe3d91'
                )
            )
        )
    );
    print_r($result);
    exit;

我遇到错误

Type: Aws\DynamoDb\Exception\DynamoDbException
Message: Error executing "GetItem" on "https://dynamodb.ap-south-1.amazonaws.com"; AWS HTTP error: Client error: `POST https://dynamodb.ap-south-1.amazonaws.com` resulted in a `400 Bad Request` response: {"__type":"com.amazon.coral.validate#ValidationException","message":"The provided key element does not match the schema" (truncated...) ValidationException (client): The provided key element does not match the schema - {"__type":"com.amazon.coral.validate#ValidationException","message":"The provided key element does not match the schema"}