There is a chance of server config problem.
Due to increased spam, hosts are starting to disable mail functions OR restrict the emails sent "FROM".
You better ask your host if there is some restrictions on the mail function or similar.
Hope this helps.
I just ran into a situation on a clients hosting account where emails generated by the system were failing, silently from the resources available to me.
I poked around in WLPE and saw it’s include of the phpmailer class which led me to /manager/includes/controls/class.phpmailer.php
In this file are blank variables for the the username and password to be used for smtp authentication. I set them to the user/pass of their hosting account and email’s been working fine since. I was a little surprised that these variables don’t appear to be exposed anywhere in the interface for configuration, considering how common it is to need smtp auth for sending mails. Odd thing, in this hosting environment just having the username and password variables populated with valid login info was enough... I didn’t need to change the SMTPAuth bool to true.
Hope this helps!