Email issues

[AvidCat]

Hi,

I have script set up on a site that I have hosted on my virtual dedicated server.

I use the plesk control panel to manage my virtual dedicated server and the site within.

The problem I have with my email replys is that not all emails are being sent by the script when someone registers on my site. About 90% of the emails are not going through. When I test this out myself it appears to work correctly, but I have about 90% of the users that sign up say they are not getting their activation emails.

I contacted the creator of this script and they just let me know that if it worked for me it should work for everyone. But they also said this:

Also make sure that your domain that you are sending mail from is not blacklisted. See: http://www.ordb.org/faq/

I am not anyway near an expert with plesk, I just started to figure out the basics. But is it possible I don't have a setting correct within plesk for emails being sent on my server or for that paticular website?

I appreciate any help, or a point in the right direction.

Thanks,
Nick