System : Odoo8 on Synology DSM 6

Suddenly this errors shown up.

What's problem? Plz help me. Thank you.

-------------------------- error message ---------------------------------

Traceback (most recent call last): File "/usr/local/lib/python2.7/site-packages/openerp/http.py", line 499, in _handle_exception return super(JsonRequest, self)._handle_exception(exception) File "/usr/local/lib/python2.7/site-packages/openerp/http.py", line 516, in dispatch result = self._call_function(**self.params) File "/usr/local/lib/python2.7/site-packages/openerp/http.py", line 282, in _call_function return checked_call(self.db, *args, **kwargs) File "/usr/local/lib/python2.7/site-packages/openerp/service/model.py", line 113, in wrapper return f(dbname, *args, **kwargs) File "/usr/local/lib/python2.7/site-packages/openerp/http.py", line 279, in checked_call return self.endpoint(*a, **kw) File "/usr/local/lib/python2.7/site-packages/openerp/http.py", line 732, in __call__ return self.method(*args, **kw) File "/usr/local/lib/python2.7/site-packages/openerp/http.py", line 375, in response_wrap response = f(*args, **kw) File "/var/packages/Odoo8/target/addons/calendar/controllers/main.py", line 61, in notify res = registry.get("calendar.alarm_manager").get_next_notif(cr, uid, context=context) File "/usr/local/lib/python2.7/site-packages/openerp/api.py", line 237, in wrapper return old_api(self, *args, **kwargs) File "/var/packages/Odoo8/target/addons/calendar/calendar.py", line 500, in get_next_notif all_notif.append(self.do_notif_reminder(cr, uid, alert, context=context)) File "/usr/local/lib/python2.7/site-packages/openerp/api.py", line 237, in wrapper return old_api(self, *args, **kwargs) File "/var/packages/Odoo8/target/addons/calendar/calendar.py", line 521, in do_notif_reminder message = event.display_time File "/usr/local/lib/python2.7/site-packages/openerp/fields.py", line 711, in __get__ self.determine_value(record) File "/usr/local/lib/python2.7/site-packages/openerp/fields.py", line 806, in determine_value record._prefetch_field(self) File "/usr/local/lib/python2.7/site-packages/openerp/api.py", line 235, in wrapper return new_api(self, *args, **kwargs) File "/usr/local/lib/python2.7/site-packages/openerp/models.py", line 3180, in _prefetch_field result = records.read(list(fnames), load='_classic_write') File "/usr/local/lib/python2.7/site-packages/openerp/api.py", line 235, in wrapper return new_api(self, *args, **kwargs) File "/usr/local/lib/python2.7/site-packages/openerp/api.py", line 552, in new_api result = method(self._model, cr, uid, self.ids, *args, **kwargs) File "/var/packages/Odoo8/target/addons/calendar/calendar.py", line 1619, in read real_data = super(calendar_event, self).read(cr, uid, [real_id for calendar_id, real_id in select], fields=fields2, context=context, load=load) File "/usr/local/lib/python2.7/site-packages/openerp/api.py", line 237, in wrapper return old_api(self, *args, **kwargs) File "/usr/local/lib/python2.7/site-packages/openerp/models.py", line 3095, in read result = BaseModel.read(records, fields, load=load) File "/usr/local/lib/python2.7/site-packages/openerp/api.py", line 235, in wrapper return new_api(self, *args, **kwargs) File "/usr/local/lib/python2.7/site-packages/openerp/models.py", line 3127, in read self._read_from_database(stored) File "/usr/local/lib/python2.7/site-packages/openerp/api.py", line 235, in wrapper return new_api(self, *args, **kwargs) File "/usr/local/lib/python2.7/site-packages/openerp/models.py", line 3276, in _read_from_database res2 = self._columns[fs[0]].get(cr, self._model, ids, fs, user, context=context, values=result) File "/usr/local/lib/python2.7/site-packages/openerp/osv/fields.py", line 1308, in get result = self._fnct(obj, cr, uid, ids, name, self._arg, context) File "/var/packages/Odoo8/target/addons/calendar/calendar.py", line 794, in _compute meeting_data[field] = self._get_display_time(cr, uid, meeting.start, meeting.stop, meeting.duration, meeting.allday, context=context) File "/usr/local/lib/python2.7/site-packages/openerp/api.py", line 237, in wrapper return old_api(self, *args, **kwargs) File "/var/packages/Odoo8/target/addons/calendar/calendar.py", line 768, in _get_display_time event_date = date.strftime(format_date)UnicodeEncodeError: 'ascii' codec can't encode character u'\ub144' in position 2: ordinal not in range(128)