The log has a bunch of these:
[2015-08-16 13:22:01] production.ERROR: ErrorException [0] : /home/dcreati/domains/dcreative.nl/public_html/invoice/app/Listeners/HandleUserSettingsChanged.php [Line 30] => Trying to get property of non-object
{“context”:“PHP”,“user_id”:0,“user_name”:"",“url”:“http://invoice.dcreative.nl”,“user_agent”:"",“ip”:“127.0.0.1”,“count”:1}
[2015-08-16 13:23:01] production.ERROR: ErrorException [0] : /home/dcreati/domains/dcreative.nl/public_html/invoice/app/Listeners/HandleUserSettingsChanged.php [Line 30] => Trying to get property of non-object
{“context”:“PHP”,“user_id”:0,“user_name”:"",“url”:“http://invoice.dcreative.nl”,“user_agent”:"",“ip”:“127.0.0.1”,“count”:1}
[2015-08-16 13:24:01] production.ERROR: ErrorException [0] : /home/dcreati/domains/dcreative.nl/public_html/invoice/app/Listeners/HandleUserSettingsChanged.php [Line 30] => Trying to get property of non-object