client.send() is not working

After login succesfully i am executing this statement
client.send(Message(text='Hi me'), thread_id=client.uid, thread_type=ThreadType.USER)
below is the error
```
Traceback (most recent call last):
File "fbTest.py", line 19, in
msg_id = client.send(Message(text='Hi me'), thread_id=client.uid, thread_type=ThreadType.USER)
File "C:\Python27\lib\site-packages\fbchat\client.py", line 951, in send return self._doSendRequest(data)
File "C:\Python27\lib\site-packages\fbchat\client.py", line 919, in _doSendRequest
j = self._post(self.req_url.SEND, data, fix_request=True, as_json=True)
File "C:\Python27\lib\site-packages\fbchat\client.py", line 127, in _post return check_request(r, as_json=as_json)
File "C:\Python27\lib\site-packages\fbchat\utils.py", line 209, in check_request
content = strip_to_json(content)
File "C:\Python27\lib\site-packages\fbchat\utils.py", line 146, in strip_to_json
raise FBchatException('No JSON object found: {}, {}'.format(repr(text), text.index('{')))
ValueError: substring not found
```