when new members try to register on my forum, no activation email is sent, even though the settings are supposed to do that. I do get a message to the member trying to activate that an email has been sent but it never arrives, this sucks, how can i fix this??? Thanks
You should try testing mail, try to send a test newsletter to your own mail , see if it arrives, try to send to various provider like hotmail, gmail, yahoo, rediff. If you are able to receive on any of the above then most probably your server is blacklisted. Inform you host about this, its host responsibility.
But before that you have verify that your php mail() function is ok, ask your host to verify that for you.
Still can't fix it, you can use SMTP mail as alternative.