I got below error when try to use mass mailing :

Error details:Type:ExceptionMessage:Invalid argument `$email`File:/home/mydomain/public_html/ow_system_plugins/base/classes/mail.phpLine:67Trace:#0 /home/mydomain/public_html/ow_system_plugins/admin/controllers/mass_mailing.php(192): BASE_CLASS_Mail->addRecipientEmail('cazhaow.qazaz@b...') #1 [internal function]: ADMIN_CTRL_MassMailing->index(Array) #2 /home/mydomain/public_html/ow_core/request_handler.php(263): call_user_func_array(Array, Array) #3 /home/mydomain/public_html/ow_core/application.php(327): OW_RequestHandler->dispatch() #4 /home/mydomain/public_html/index.php(73): OW_Application->handleRequest() #5 {main}