Connection refused when using bitcoinrpc on Linux

Question

I am new to python-bitcoinrpc(also new to VM Linux actually) and I want to use the blockchain parser from alecalve to get ordered blocks. I used Windows to download the blockchain data into an external hard drive as well as bitcoin.conf but then I found that this parser could only be used on Linux, so I downloaded Bitcoin Core again on Linux and run

./bitcoin-qt -datadir=/media/myharddrive/Bitcoin -conf=/media/myharddrive/Bitcoin/bitcoin.conf

to avoid re-downloading the data.

However, it seems I cannot connect to rpc because the simple code

rpc_connection = AuthServiceProxy("http://%s:%[email protected]:8332"%('rpcuser', 'myrpcpassword'))

best_block_hash = rpc_connection.getbestblockhash()

returns error like this

Traceback (most recent call last):
  File "process1.py", line 129, in <module>
    parser(block)
  File "process1.py", line 62, in parser
    prevtxhex = rpc_connection.getrawtransaction(prevtxidhash,0)
  File "/home/lylian/.local/lib/python3.8/site-packages/bitcoinrpc/authproxy.py", line 132, in __call__
    self.__conn.request('POST', self.__url.path, postdata,
  File "/usr/lib/python3.8/http/client.py", line 1230, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/usr/lib/python3.8/http/client.py", line 1276, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/usr/lib/python3.8/http/client.py", line 1225, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/usr/lib/python3.8/http/client.py", line 1004, in _send_output
    self.send(msg)
  File "/usr/lib/python3.8/http/client.py", line 944, in send
    self.connect()
  File "/usr/lib/python3.8/http/client.py", line 915, in connect
    self.sock = self._create_connection(
  File "/usr/lib/python3.8/socket.py", line 808, in create_connection
    raise err
  File "/usr/lib/python3.8/socket.py", line 796, in create_connection
    sock.connect(sa)
ConnectionRefusedError: [Errno 111] Connection refused

I wonder if it's because my code cannot find bitcoin.conf(I put it both in the default location and my hard drive) or there is something wrong with my settings.

rpcuser=xxx
rpcpassword=xxx
server=1

Thanks very much!!