I am with Streamline.net
and i have the unlimited hosting package how ever i cannot send mail via SMTP AUTHSMTP, SENDMAIL or PHPMAIL

my AUTHSMTP setting are
SMTP server: authsmtp.streamline.net
SMTP username: your email address (ie root@mattjaco.co.uk)
SMTP password: your password
SMTP port: 25

How ever i get this error when someone signed up

You are now registered. However, we were unable to send the activation mail to your email account due to an internal error that had occurred on our server. We are sorry for the inconvenience, please send the webmaster an email notifying him/her of the situation.

can anyone offer any help.

cheers

nick