I get the following error message in admin/user/user:
Unable to send e-mail. Please contact the site administrator if the problem persists.
Is this error caused by the fact I haven't an email service installed on my server? thanks
Update: I now get the following error.
Error sending e-mail (from "Website Name" to email@gmail.com). Attempt to e-mail email@gmail.com concerning order 114 failed.
This error is due the fact that your mail service is not configured. Drupal, by default, trying to send the user some email and after it fail, it show this message.
If you Drupal is running on Ubuntu it is quite easy to install the mail service:
sudo apt-get install php-pear sudo pear install mail sudo pear install Net_SMTP sudo pear install Auth_SASL sudo pear install mail_mime sudo apt-get install postfix
And that's it!