On A Unix server, you should select Mail for Unix.
There really is no reason to start a new thread for this problem, you already have a thread open with the same issue that we are working on. Instead of starting a new thread, it would be better to continue the old thread.
I have started a support ticket so we can get to the bottom of this issue. to view and edit your support ticket, please log into your support history:
supporthistory.php