After i use POS, i want to close session but can not. Please help me! Here is error i got:

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Odoo Server Error
Traceback (most recent call last):
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\base\models\ir_http.py", line 237, in _dispatch
    result = request.dispatch()
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\http.py", line 684, in dispatch
    result = self._call_function(**self.params)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\http.py", line 360, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\service\model.py", line 94, in wrapper
    return f(dbname, *args, **kwargs)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\http.py", line 348, in checked_call
    result = self.endpoint(*a, **kw)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\http.py", line 913, in __call__
    return self.method(*args, **kw)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\http.py", line 532, in response_wrap
    response = f(*args, **kw)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\web\controllers\main.py", line 1393, in call_button
    action = self._call_kw(model, method, args, kwargs)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\web\controllers\main.py", line 1381, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\api.py", line 396, in call_kw
    result = _call_kw_multi(method, model, args, kwargs)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\api.py", line 383, in _call_kw_multi
    result = method(recs, *args, **kwargs)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\point_of_sale\models\pos_session.py", line 279, in action_pos_session_closing_control
    session.action_pos_session_close()
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\point_of_sale\models\pos_session.py", line 309, in action_pos_session_close
    return self._validate_session()
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\point_of_sale\models\pos_session.py", line 326, in _validate_session
    self.with_company(self.company_id)._create_account_move()
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\point_of_sale\models\pos_session.py", line 421, in _create_account_move
    'ref': self.name,
  File "", line 2, in create
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\api.py", line 344, in _model_create_multi
    return create(self, [arg])
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\account\models\account_move.py", line 1959, in create
    rslt = super(AccountMove, self).create(vals_list)
  File "", line 2, in create
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\api.py", line 345, in _model_create_multi
    return create(self, arg)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\mail\models\mail_thread.py", line 264, in create
    threads = super(MailThread, self).create(vals_list)
  File "", line 2, in create
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\api.py", line 345, in _model_create_multi
    return create(self, arg)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\base\models\ir_fields.py", line 534, in create
    recs = super().create(vals_list)
  File "", line 2, in create
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\api.py", line 345, in _model_create_multi
    return create(self, arg)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\models.py", line 3870, in create
    records = self._create(data_list)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\models.py", line 4043, in _create
    records._validate_fields(name for data in data_list for name in data['stored'])
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\models.py", line 1266, in _validate_fields
    check(self)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\account\models\sequence_mixin.py", line 61, in _constrains_date_sequence
    sequence = record[record._sequence_field]
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\models.py", line 5668, in __getitem__
    return self._fields[key].__get__(self, type(self))
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\fields.py", line 967, in __get__
    self.recompute(record)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\fields.py", line 1153, in recompute
    self.compute_value(recs)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\fields.py", line 1175, in compute_value
    records._compute_field_value(self)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\mail\models\mail_thread.py", line 410, in _compute_field_value
    return super()._compute_field_value(field)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\models.py", line 4063, in _compute_field_value
    getattr(self, field.compute)()
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\account\models\account_move.py", line 1136, in _compute_name
    highest_name = self[0]._get_last_sequence() if self else False
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\addons\account\models\sequence_mixin.py", line 179, in _get_last_sequence
    self.env.cr.execute(query, param)
  File "", line 2, in execute
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\sql_db.py", line 101, in check
    return f(self, *args, **kwargs)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\sql_db.py", line 298, in execute
    res = self._obj.execute(query, params)
Exception

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\http.py", line 640, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "C:\Program Files\Odoo 14.0.20211001\server\odoo\http.py", line 316, in _handle_exception
    raise exception.with_traceback(None) from new_cause
psycopg2.errors.InvalidRegularExpression: invalid regular expression: quantifier operand invalid