This issue caused by this plugin "System - ParaInvite"
Notice: Undefined variable: app in /home/creoenecuador/public_html/plugins/system/parainvite_system/parainvite_system.php on line 63
Fatal error: Call to a member function redirect() on null in /home/creoenecuador/public_html/plugins/system/parainvite_system/parainvite_system.php on line 63