python 的 EOFError: EOF when reading a line 是什么原因？

在程序执行过程中，出现过如题的错误信息。

google了一些，好像是python或部署的原因，但是有这些错误信息：

Traceback (most recent call last):

...

File "/usr/local/lib/python2.7/urllib.py", line 84, in urlopen
return opener.open(url)

File "/usr/local/lib/python2.7/urllib.py", line 205, in open
return getattr(self, name)(url)

File "/usr/local/lib/python2.7/urllib.py", line 356, in open_http
return self.http_error(url, fp, errcode, errmsg, headers)

File "/usr/local/lib/python2.7/urllib.py", line 369, in http_error
result = method(url, fp, errcode, errmsg, headers)

File "/usr/local/lib/python2.7/urllib.py", line 663, in http_error_301
return self.http_error_302(url, fp, errcode, errmsg, headers, data)

File "/usr/local/lib/python2.7/urllib.py", line 632, in http_error_302
data)

File "/usr/local/lib/python2.7/urllib.py", line 659, in redirect_internal
return self.open(newurl)

File "/usr/local/lib/python2.7/urllib.py", line 205, in open
return getattr(self, name)(url)

File "/usr/local/lib/python2.7/urllib.py", line 356, in open_http
return self.http_error(url, fp, errcode, errmsg, headers)

File "/usr/local/lib/python2.7/urllib.py", line 369, in http_error
result = method(url, fp, errcode, errmsg, headers)

File "/usr/local/lib/python2.7/urllib.py", line 694, in http_error_401
return getattr(self,name)(url, realm)

File "/usr/local/lib/python2.7/urllib.py", line 758, in retry_http_basic_auth
user, passwd = self.get_user_passwd(host, realm, i)

File "/usr/local/lib/python2.7/urllib.py", line 787, in get_user_passwd
user, passwd = self.prompt_user_passwd(host, realm)

File "/usr/local/lib/python2.7/urllib.py", line 796, in prompt_user_passwd
host))

EOFError: EOF when reading a line

这是权限问题？

到底是什么问题呢？