Server Config is having an error 500 with ISPConfig Version: 3.1.13p1
Found a bug in file interface/web/admin/server_config_edit.php
line 110
-- $app->tpl->setVar('server_name', $app->functions->htmlentities($app->db->queryOneRecord("SELECT server_name FROM server WHERE server_id = ? AND ((SELECT COUNT(*) FROM server) > 1)", $this->id)['server_name']));
++ $app->tpl->setVar('server_name', $app->functions->htmlentities($app->db->queryOneRecord("SELECT server_name FROM server WHERE server_id = ? AND ((SELECT COUNT(*) FROM server) > 1)", $this->id)));