Post to your WordPress.org site using email
The following is a nice summary and comments by neoscrib of what is required, as explained by people at WordPress.org.
You need to run wp-mail.php in your wordpress install directory. There's are several ways to do this.
1. Manually browse to http://blog.example.com/wp-mail.php in a web browser. 2. Setup a cron job in your cpanel to execute the following command every so often.
wget -N http://blog.example.com/wp-mail.php
3. Setup a cron job in your cpanel to execute the following command every so often.
php /full/path/to/your/wp-mail.php
There are other ways, but those three are the easiest. I'd recommend the last option. The wp-mail.php scripts will only check mail at a maximum every 5 minutes. If you don't write very often, I'd recommend setting up your cron to run as infrequent as possible (once a day). If you do write frequenty, I'd recommend setting up the cron to run at a maximum every 15 minutes. You could do it more frequenty (but no more frequently than every 5 minutes, unless you edit wp-mail.php), but I don't see why you would need to.
If you've already done that, the only other things I can see is that you didn't mention in your original post setting the port number in the WordPress settings. The port should be 110 unless you want to use SSL, then you want port 995. If you do intend to use SSL then you'll want to change the server setting to ssl://mail.example.com. It looks like your email server and wordpress blog are on the same server so I'd actually recommend using localhost instead of mail.example.com.
Check also