Odoo Server Error

Traceback (most recent call last):
  File "/data/build/odoo/odoo/http.py", line 627, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/data/build/odoo/odoo/http.py", line 317, in _handle_exception
    raise pycompat.reraise(type(exception), exception, sys.exc_info()[2])
  File "/data/build/odoo/odoo/tools/pycompat.py", line 14, in reraise
    raise value
  File "/data/build/odoo/odoo/http.py", line 672, in dispatch
    result = self._call_function(**self.params)
  File "/data/build/odoo/odoo/http.py", line 353, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/data/build/odoo/odoo/service/model.py", line 93, in wrapper
    return f(dbname, *args, **kwargs)
  File "/data/build/odoo/odoo/http.py", line 346, in checked_call
    result = self.endpoint(*a, **kw)
  File "/data/build/odoo/odoo/http.py", line 917, in __call__
    return self.method(*args, **kw)
  File "/data/build/odoo/odoo/http.py", line 518, in response_wrap
    response = f(*args, **kw)
  File "/data/build/odoo/addons/im_livechat/controllers/main.py", line 130, in feedback
    rating = channel.rating_ids[0]
  File "/data/build/odoo/odoo/models.py", line 5424, in __getitem__
    return self.browse((self._ids[key],))
IndexError: tuple index out of range