I've latest 0.9.3 version of WP Mail SMTP plugin.
Send all WordPress emails via SMTP -> option not working
Use the PHP mail() function to send emails -> option working
Why first option not working? I've used it before, and it was working.
Its happening from last 3-4 months. May be I had wordpress 3.5-3.6 version.
I tried with same mail server settings for both...