CiviCRM 4.6.10 for Drupal 7.41 Outbound email setting: either "Mail" or "Sendmail" Both system test were successfully, CiviCRM contribution form email receipts are working. However, no mails were received when test from Activity's "Send an email" and "Scheduled Reminder"
P.S. On the same server and same outbound settings, my other instance with CiviCRM 4.26 works just fine.
Can someone please help?