First, make sure Scoop is configured to use the right mail server by checking your configuration against the instructions in section 2.5.2.
If Scoop is configured properly, try creating an account using an email address you know for certain the mail server Scoop uses can successfully send email to. It is entirely possible that the address that didn't receive the email has an overzealous spam filter, and there's actually nothing at all wrong with your configuration. In that case, there's really nothing you can do.
If Scoop can't send an email to an address that you know for sure works and you can send email to via the same mailserver as Scoop is configured to use, then you'll have to check the mailserver logs to see what is actually happening to the email, because the problem is probably in the mail server configuration itself, possibly an issue with your Scoop server not having permission to relay email through the mail server.
If you've installed Scoop on Windows, we know email doesn't work but we don't know why yet.