Reports in the Web Security Service (WSS) show that the verdicts are either policy_denied or content_filter_denied.
Can I unblock (allow) a website with these verdicts?
As you are reviewing reports, you might question the categorization and want to ask Symantec to review that rating and suggest an alternate category. Symantec cannot guarantee a rating switch but will perform an analysis.
How to request a review and re-rating for a domain or IP: SiteReview
If you request is rejected, you can add the site to the Web Security Service "always allow" (G3) or "always block" (G4) global rules. Use the Content Filtering policy editor to exempt those domains or URLs.