We are sending emails to users with the emailTemplate_load function and it is throwing this error (This is a multi-part message in MIME format.------_mixed_2d3886c11d6c4a5999535 then the rest in plain text) for .icloud, .mac, & .me addresses

the email is only using $PLACEHOLDERS tag to pull in the content

Here is the code that is sending the email:

// send email to user
                $emailTemplate = "email/email_reset_password2.php";
                $emailHeaders  = emailTemplate_load(array(
                      'template'     => websiteLogin_pluginDir() . "/$emailTemplate",
                      'subject'      => '', // set in template
                      'from'         => '', // set in template
                      'to'           => $user['email'],
                      'placeholders' => array(
                      'firstname'      => mb_convert_case($user['firstname'], MB_CASE_TITLE, "UTF-8"),
                      'lastname'       => mb_convert_case($user['lastname'], MB_CASE_TITLE, "UTF-8"),
                      'resetUrl'       => $resetQuery,
                      ),
                    ));
                $mailErrors   = sendMessage($emailHeaders);
                if ($mailErrors) { die("Mail Error: $mailErrors"); 
                }

Thanks!