Win10安装Tensorflow出错：socket.timeout: The read operation timed out

Windows10系统用pip3安装Tensorflow指定版本（之前安装的2.1.0版本太高了）：

(tensorflow) C:\Users\XXX>pip3 install tensorflow==1.2.1

出错：

WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ReadTimeoutError("HTTPSConnectionPool(host='pypi.org', port=443): Read timed out. (read timeout=15)",)': /simple/tensorflow/
Collecting tensorflow==1.2.1
  Downloading tensorflow-1.2.1-cp35-cp35m-win_amd64.whl (21.2 MB)
     |█                               | 665 kB 6.1 kB/s eta 0:55:57ERROR: Exception:
Traceback (most recent call last):
  File "c:\programdata\anaconda3\envs\tensorflow\lib\site-packages\pip\_vendor\urllib3\response.py", line 425, in _error_catcher
    yield
  File "c:\programdata\anaconda3\envs\tensorflow\lib\site-packages\pip\_vendor\urllib3\response.py", line 507, in read
    data = self._fp.read(amt) if not fp_closed else b""
  File "c:\programdata\anaconda3\envs\tensorflow\lib\site-packages\pip\_vendor\cachecontrol\filewrapper.py", line 62, in read
    data = self.__fp.read(amt)
  File "c:\programdata\anaconda3\envs\tensorflow\lib\http\client.py", line 448, in read
    n = self.readinto(b)
  File "c:\programdata\anaconda3\envs\tensorflow\lib\http\client.py", line 488, in readinto
    n = self.fp.readinto(b)
  File "c:\programdata\anaconda3\envs\tensorflow\lib\socket.py", line 576, in readinto
    return self._sock.recv_into(b)
  File "c:\programdata\anaconda3\envs\tensorflow\lib\ssl.py", line 937, in recv_into
    return self.read(nbytes, buffer)
  File "c:\programdata\anaconda3\envs\tensorflow\lib\ssl.py", line 799, in read
    return self._sslobj.read(len, buffer)
  File "c:\programdata\anaconda3\envs\tensorflow\lib\ssl.py", line 583, in read
    v = self._sslobj.read(len, buffer)
socket.timeout: The read operation timed out

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\programdata\anaconda3\envs\tensorflow\lib\site-packages\pip\_internal\cli\base_command.py", line 186, in _main
    status = self.run(options, args)
  File "c:\programdata\anaconda3\envs\tensorflow\lib\site-packages\pip\_internal\commands\install.py", line 331, in run
    resolver.resolve(requirement_set)
  File "c:\programdata\anaconda3\envs\tensorflow\lib\site-packages\pip\_internal\legacy_resolve.py", line 177, in resolve
    discovered_reqs.extend(self._resolve_one(requirement_set, req))
  File "c:\programdata\anaconda3\envs\tensorflow\lib\site-packages\pip\_internal\legacy_resolve.py", line 333, in _resolve_one
    abstract_dist = self._get_abstract_dist_for(req_to_install)
  File "c:\programdata\anaconda3\envs\tensorflow\lib\site-packages\pip\_internal\legacy_resolve.py", line 282, in _get_abstract_dist_for
    abstract_dist = self.preparer.prepare_linked_requirement(req)
  File "c:\programdata\anaconda3\envs\tensorflow\lib\site-packages\pip\_internal\operations\prepare.py", line 482, in prepare_linked