为什么urlopen不适用于某些网站？

我对python很陌生，我正尝试从客户的网站上抓取一些基本数据。我在其他网站上尝试了完全相同的方法，并收到了预期的结果。这是我到目前为止所拥有的：

from urllib.request import urlopen
from bs4 import BeautifulSoup

main_url = 'https://www.grainger.com/category/pipe-hose-tube-fittings/hose-products/hose-fittings-couplings/cam-groove-fittings-gaskets/metal-cam-groove-fittings/stainless-steel-cam-groove-fittings'

uClient = urllib.request.urlopen(main_url)
main_html = uClient.read()
uClient.close()

甚至这个简单的阅读网站电话都导致了超时错误。正如我所说，我已经在其他网站上成功使用了完全相同的代码。错误是：

Traceback (most recent call last):
  File "Pricing_Tool.py", line 6, in <module>
    uClient = uReq(main_url)
  File "C:\Users\Brian Knoll\anaconda3\lib\urllib\request.py", line 222, in urlopen
    return opener.open(url, data, timeout)
  File "C:\Users\Brian Knoll\anaconda3\lib\urllib\request.py", line 525, in open
    response = self._open(req, data)
  File "C:\Users\Brian Knoll\anaconda3\lib\urllib\request.py", line 543, in _open
    '_open', req)
  File "C:\Users\Brian Knoll\anaconda3\lib\urllib\request.py", line 503, in _call_chain
    result = func(*args)
  File "C:\Users\Brian Knoll\anaconda3\lib\urllib\request.py", line 1362, in https_open
    context=self._context, check_hostname=self._check_hostname)
  File "C:\Users\Brian Knoll\anaconda3\lib\urllib\request.py", line 1322, in do_open
    r = h.getresponse()
  File "C:\Users\Brian Knoll\anaconda3\lib\http\client.py", line 1344, in getresponse
    response.begin()
  File "C:\Users\Brian Knoll\anaconda3\lib\http\client.py", line 306, in begin
    version, status, reason = self._read_status()
  File "C:\Users\Brian Knoll\anaconda3\lib\http\client.py", line 267, in _read_status
    line = str(self.fp.readline(_MAXLINE + 1), "iso-8859-1")
  File "C:\Users\Brian Knoll\anaconda3\lib\socket.py", line 589, in readinto
    return self._sock.recv_into(b)
  File "C:\Users\Brian Knoll\anaconda3\lib\ssl.py", line 1071, in recv_into
    return self.read(nbytes, buffer)
  File "C:\Users\Brian Knoll\anaconda3\lib\ssl.py", line 929, in read
    return self._sslobj.read(len, buffer)
TimeoutError: [WinError 10060] A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond

该网站是否可能太大而无法处理？任何帮助将不胜感激。谢谢！