why i get order. Margin status

[z2014]

when i set 30mins datas, and when i buy price, the order get margin
i am sure i get enough money,here is the code.

import datetime
import os.path
import sys
import backtrader as bt
import talib
import numpy as np 
import matplotlib
import math
import pandas as pd

fastperiod = 12
slowperiod = 26
signalperiod = 9
class MACDStrategy(bt.Strategy):

    def log(self, txt, dt=None):
        dt = dt or self.datas[0].datetime.date(0)
        print('%s, %s' % (dt.isoformat(), txt))

    def __init__(self):
        self.dataclose = self.datas[0].close
        self.order = None
        # bt.indicators.MACDHisto(self.datas[0], period_me1=fastperiod, period_me2=slowperiod, period_signal=signalperiod)
        bt.indicators.SMA(self.datas[0], period=13)

    def notify_order(self, order):
        # 前一天下单，以后一天的价格成交
        if order.status in [order.Submitted, order.Accepted]:
            return
        if order.status in [order.Completed]:
            if order.isbuy():
                self.log('BUY EXECUTED, %.2f' % order.executed.price)
            elif order.issell():
                self.log('SELL EXECUTED, %.2f' % order.executed.price)
        print('clear self.order')
        self.order = None

    def next(self):
        close = np.array(self.dataclose.get(ago=0, size=self.__len__()))
        macd, macdsignal, macdhist = talib.MACD(close, fastperiod=fastperiod, slowperiod=slowperiod, signalperiod=signalperiod)
        ma13 = talib.MA(close, timeperiod=13)
        
        if self.order:
            return
        if not self.position:
            # if macdhist[-1] > 0 and macd[-1] > 0:
            if close[-1] > ma13[-1]:
                print('buy', close[-1], ma13[-1])
                self.order = self.buy()

        else:
            # if macdhist[-1] < 0 and macd[-1] < 0:
            if close[-1] < ma13[-1]:
                print('sell', close[-1], ma13[-1])
                self.order = self.sell()

class FixedSize(bt.Sizer):
 
    def _getsizing(self, comminfo, cash, data, isbuy):
        position = self.broker.getposition(data)

        if isbuy:
            return math.floor(cash/data.open)

        return position.size

if __name__ == '__main__':
    cerebro = bt.Cerebro()

    cerebro.addstrategy(MACDStrategy)
    cerebro.addsizer(FixedSize)

    # modpath = os.path.dirname(os.path.abspath(sys.argv[0]))
    # datapath = os.path.join(modpath, './datas/0700.HK.csv')

    # 加载提前从雅虎金融下载的股价
    # data = bt.feeds.YahooFinanceCSVData(
    #     dataname=datapath,
    #     fromdate=datetime.datetime(2022, 1, 1, 10, 0, 0),
    #     todate=datetime.datetime(2022, 1, 28, 16, 0, 0),
    #     reverse=False)

    dataframe = pd.read_csv('./datas/0700.HK.30min.csv', index_col=0, parse_dates=True)
    data = bt.feeds.PandasData(
        dataname=dataframe,
        fromdate=datetime.datetime(2021, 1, 1),
        todate=datetime.datetime(2021, 2, 4),
        timeframe=bt.TimeFrame.Minutes
        )
        
    # timeframe=bt.TimeFrame.Minutes
    cerebro.adddata(data)

    # 设置初始现金
    cerebro.broker.setcash(100000.0)

    # 设置佣金
    cerebro.broker.setcommission(commission=0.001)

    print('Starting Portfolio Value: %.2f' % cerebro.broker.getvalue())

    cerebro.run()

    print('Final Portfolio Value: %.2f' % cerebro.broker.getvalue())

    cerebro.plot()