Order cannot be filled successfully

[kelvintfy]

Hi All! I am debugging a problem that some of the orders are not filled successfully. The strategy I am using is when ma50 crossover upper band of bollinger band, it will try to fill the order. It will close the position for vice versa. However, a lot of self.buy() orders are not filled successfully and led to empty self.position and thereby no position is closed (we can notice this by telling no Sell is printed in the console). How could I force every self.buy() to execute successfully?
I have tried trade_on_close=True but the problem still persists..

from backtesting import Strategy
# from backtesting.lib import crossover, cross
class BollCrossAddress(Strategy):   
    ma = 50
    sd = 0.8
    indicator = 'ma50'
        
    def init(self):
        self.addr_boll_upper = self.I(bbands_upper, self.data[self.indicator], self.ma, self.sd)
        
    def next(self):                
        if not self.position:
            if crossover(self.data[self.indicator], self.addr_boll_upper):
                print(f'Buy: {self.data.index[-1]}, {self.data[self.indicator][-1]}, {self.addr_boll_upper[-1]}')
                self.buy()
        
        if self.position:
            if crossover(self.addr_boll_upper, self.data[self.indicator]):
                print(f'Sell: {self.data.index[-1]}, {self.data[self.indicator][-1]}, {self.addr_boll_upper[-1]}')
                self.position.close()

From the following data, I found that only 6 orders are filled successfully (the ones with both Buy and Sell). There are a lot of orders are not filled, it can be deduced from NO sell is printed in the console after Buy.

Buy: 2020-02-18 00:00:00, 17282.0, 14863.729507783846
Buy: 2020-04-23 00:00:00, 11268.0, 11020.978104983029
Sell: 2020-05-22 00:00:00, 13082.0, 13033.164937884701
Buy: 2020-05-28 00:00:00, 13485.0, 13242.868919419836
Sell: 2020-07-23 00:00:00, 13388.0, 13370.974680759127
Buy: 2020-10-10 00:00:00, 18467.0, 18169.470221837113
Sell: 2020-12-12 00:00:00, 26261.0, 26130.28378996304
Buy: 2021-02-03 00:00:00, 81917.0, 81595.43879917824
Buy: 2021-02-05 00:00:00, 82103.0, 81888.70986872
Buy: 2021-03-01 00:00:00, 94213.0, 93894.04299881222
Buy: 2021-03-03 00:00:00, 98497.0, 94625.6306463398
Buy: 2021-03-07 00:00:00, 98894.0, 95818.56244779077
Buy: 2021-03-29 00:00:00, 103895.0, 103143.5318240221
Buy: 2021-04-04 00:00:00, 104392.0, 104337.9938051144
Buy: 2021-04-10 00:00:00, 105368.0, 104818.7651040614
Buy: 2021-07-26 00:00:00, 80551.0, 79591.71471845351
Buy: 2021-09-01 00:00:00, 92331.0, 91450.38538573349
Buy: 2021-10-05 00:00:00, 98220.0, 93379.71465684906
Buy: 2021-11-07 00:00:00, 107841.0, 106707.50174184672
Buy: 2022-02-28 00:00:00, 87706.0, 86549.69993292577
Buy: 2022-03-09 00:00:00, 86819.0, 86292.36936749419

[kelvintfy]

this issue has been resolved. It is because of insufficient amount of cash... Thank you for this amazing library and all the amazing people!