Norton Safe Web uses Norton Accounts to manage user accounts. When you signed up for an account on Norton Safe Web, a Norton Account was created for you. If you need to change your password, then login to your Norton Account and select "Change Password".
I don't believe there's anything malicious here, aside from the fact it's a new website. Norton is claiming it's a "known dangerous web page" but doesn't say why. I'm inclined to believe it's just that it's a new site.
Thanks for joining the Norton Safe Web community. Since this is your first time signing in, please provide a display name for yourself. This is the name that will be associated with your reviews. It will be viewable by everyone. You will not be able to change it later.