Error:
Odoo Server Error

Traceback (most recent call last):
  File "/data/build/odoo/odoo/http.py", line 623, 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 668, in dispatch
    result = self._call_function(**self.params)
  File "/data/build/odoo/odoo/http.py", line 349, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/data/build/odoo/odoo/service/model.py", line 92, in wrapper
    return f(dbname, *args, **kwargs)
  File "/data/build/odoo/odoo/http.py", line 342, in checked_call
    result = self.endpoint(*a, **kw)
  File "/data/build/odoo/odoo/http.py", line 886, in __call__
    return self.method(*args, **kw)
  File "/data/build/odoo/odoo/http.py", line 514, in response_wrap
    response = f(*args, **kw)
  File "/data/build/odoo/addons/web/controllers/main.py", line 1108, in call_kw
    return self._call_kw(model, method, args, kwargs)
  File "/data/build/odoo/addons/web/controllers/main.py", line 1100, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/data/build/odoo/odoo/api.py", line 390, in call_kw
    result = _call_kw_model(method, model, args, kwargs)
  File "/data/build/odoo/odoo/api.py", line 363, in _call_kw_model
    result = method(recs, *args, **kwargs)
  File "/data/build/odoo/addons/web/models/models.py", line 73, in web_read_group
    expand_limit, expand_orderby)
  File "/data/build/odoo/addons/web/models/models.py", line 97, in _web_read_group
    orderby=orderby, lazy=lazy)
  File "/data/build/odoo/odoo/models.py", line 2066, in read_group
    result = self._read_group_raw(domain, fields, groupby, offset=offset, limit=limit, orderby=orderby, lazy=lazy)
  File "/data/build/odoo/odoo/models.py", line 2103, in _read_group_raw
    assert gb_field.store and gb_field.column_type, "Fields in 'groupby' must be regular database-persisted fields (no function or related fields), or function fields with store=True"
AssertionError: Fields in 'groupby' must be regular database-persisted fields (no function or related fields), or function fields with store=True