【Python】ccxtを使用し、Binanceにて自動売買プログラムを実行しようとしたところ・・・

当方、Python経験一週間以内のド素人です。
ccxtを使用し、Binanceにて自動売買プログラムを実行しようとしました。
（API key と Secret keyはマスクしてます）

import time
import pandas as pd
import ccxt
import talib as ta
import requests

exchange = ccxt.binance()
exchange.apiKey = 'XXXXX'
exchange.secret = 'XXXXX'

### カスタマイズ項目 ###
crypto = 'SOL'          # 取引する仮想通貨
currency = 'BUSD'       # BUSD建て
interval = 60*1         # チャート足（60*5なら 5分足）
duration = 20           # 移動平均のサイズ
trading_amount = 500    # 一度の売買で使う金額（単位=currency）
dif = 0.8               # 購入時からの差額
### カスタマイズ項目ここまで ###

symbol = crypto + '/' + currency
position = 0            # 自動売買中に持っているポジション
last_rate = 0           # 最後に約定したレート（単位=currency）

df = pd.DataFrame()

while True:
  time.sleep(interval)

  ticker_info = exchange.fetch_ticker(symbol)
  df = pd.concat([df, pd.DataFrame({'price': [ticker_info['last']]})], ignore_index=True)

  if len(df) < duration:
    continue

  df['upper'], df['middle'], df['lower'] = ta.BBANDS(df['price'], timeperiod=duration, nbdevup=2, nbdevdn=2, matype=0)

  if position:   #売却
    #購入時からの差額が、difで設定した金額より大きくなった場合
    if ticker_info['last'] > last_rate + dif or ticker_info['last'] < last_rate - dif:
      exchange.create_order(symbol=symbol, type='market', side='sell', amount=position)
      position = 0

  else:   #購入
    ticker_balance = exchange.fetch_balance()
    if float(ticker_balance[currency]['free']) > trading_amount and df['price'].iloc[-1] < df['lower'].iloc[-1]:
      amount = round(trading_amount / float(ticker_info['last']), 5)
      exchange.create_order(symbol=symbol, type='market', side='buy', amount=amount)
      position = amount
      last_rate = ticker_info['last']

  df = df.iloc[1:, :]

上記のコードで購入はできたのですが、売却時に下記エラーが出てしまいます。
解決方法を教えて頂けないでしょうか。（こちらも一部マスクしてます）

Traceback (most recent call last):
  File "C:\Users\XXXXX\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\ccxt\base\exchange.py", line 655, in fetch
    response.raise_for_status()
  File "C:\Users\XXXXX\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\requests\models.py", line 960, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 400 Client Error: Bad Request for url: https://api.binance.com/api/v3/order

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "G:\XXXXX\teratail_test.py", line 40, in <module>
    exchange.create_order(symbol=symbol, type='market', side='sell', amount=position)
  File "C:\Users\XXXXX\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\ccxt\binance.py", line 2788, in create_order
    response = getattr(self, method)(self.extend(request, params))
  File "C:\Users\XXXXX\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\ccxt\base\exchange.py", line 495, in inner
    return entry(_self, **inner_kwargs)
  File "C:\Users\XXXXX\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\ccxt\binance.py", line 5070, in request
    response = self.fetch2(path, api, method, params, headers, body, config, context)
  File "C:\Users\XXXXX\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\ccxt\base\exchange.py", line 542, in fetch2
    return self.fetch(request['url'], request['method'], request['headers'], request['body'])
  File "C:\Users\XXXXX\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\ccxt\base\exchange.py", line 671, in fetch
    skip_further_error_handling = self.handle_errors(http_status_code, http_status_text, url, method, headers, http_response, json_response, request_headers, request_body)
  File "C:\Users\XXXXX\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\ccxt\binance.py", line 5026, in handle_errors
    self.throw_exactly_matched_exception(self.exceptions['exact'], message, self.id + ' ' + message)
  File "C:\Users\XXXXX\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\ccxt\base\exchange.py", line 560, in throw_exactly_matched_exception
    raise exact[string](message)
ccxt.base.errors.InsufficientFunds: binance Account has insufficient balance for requested action.