python之使用 python pysftp 包，出现 "SSHException: Bad host key from server"错误

我正在运行带有 pysftp 包的 Python 3，版本 0.2.9。

我的以下代码在这里。我正在正确加载主机 key ，如行 cnopts.hostkeys.keys() 所示。

import pysftp 
 
key_file_test = './path_to_key_file/key_file.pub' 
 
DOWNLOAD_UAT = { 
    "USERNAME": "xxxxxxxx", 
    "PASSWORD": "xxxxxxxx" 
} 
 
UAT_FTP_SITE = 'sftp-test.site.com' 
 
cnopts = pysftp.CnOpts() 
cnopts.hostkeys.load(key_file_test) 
cnopts.hostkeys.keys() 
 
'''['github.com', 'XXX.XX.XXX.XXX', 'sftp-test.site.com']''' 
 
srv = pysftp.Connection(host=UAT_SFTP_SITE, username=DOWNLOAD_UAT['USERNAME'],  
                        password=DOWNLOAD_UAT['PASSWORD'], cnopts=cnopts, port=22) 

那么当我运行最后一行时我的错误是

--------------------------------------------------------------------------- 
SSHException                              Traceback (most recent call last) 
<ipython-input-82-308ec955a92e> in <module>() 
      8  
      9 srv = pysftp.Connection(host=UAT_SFTP_SITE, username=DOWNLOAD_UAT['USERNAME'],  
---> 10                         password=DOWNLOAD_UAT['PASSWORD'], cnopts=cnopts, port=22) 
     11 data = srv.listdir() 
 
C:\ProgramData\Anaconda3\lib\site-packages\pysftp\__init__.py in __init__(self, host, username, private_key, password, port, private_key_pass, ciphers, log, cnopts, default_path) 
    141         self._transport.use_compression(self._cnopts.compression) 
    142         self._set_authentication(password, private_key, private_key_pass) 
--> 143         self._transport.connect(**self._tconnect) 
    144  
    145     def _set_authentication(self, password, private_key, private_key_pass): 
 
C:\ProgramData\Anaconda3\lib\site-packages\paramiko\transport.py in connect(self, hostkey, username, password, pkey, gss_host, gss_auth, gss_kex, gss_deleg_creds) 
   1139                     key.get_name(), repr(key.asbytes())) 
   1140                 ) 
-> 1141                 raise SSHException('Bad host key from server') 
   1142             self._log(DEBUG, 'Host key verified (%s)' % hostkey.get_name()) 
   1143  
 
SSHException: Bad host key from server 

有谁知道这里的问题是什么？