Hello, hope that someone can help me out on this. When I try to create an appointment in the calendar I can do it without any troubles but only and only if I don't add any attendee. If I add an attendee when I press the create button Odoo shows this error:

Failed to render template <Template memory:7f9ab2c5ad50> using values {'format_tz': <function <lambda> at 0x7f9ab37725f0>, 'ctx': {u'lang': u'en_US', u'tz': False, u'uid': 1, 'color': {'accepted': 'green', 'declined': 'red', 'needsAction': 'grey', 'tentative': '#FFFF00'}, 'safe': False, 'base_url': u'http://104.196.23.8:8069', u'params': {u'action': 258, u'menu_id': 191, u'model': u'calendar.event', u'_push_me': False, u'view_type': u'calendar'}, 'dbname': u'xxx_DB_NAME_OMITTED_xxx', 'action_id': 258}, 'user': res.users(1,), 'object': calendar.attendee(60,)}

Can someone guide me or help me out on this? Haven't been able to find any solution to it. I have V9 and just upgraded to the latest build (20160528) to see if it was a bug from an older build but it's still present.

Thanks in advanced.