Lots of companies use Internet Filters on their network to prevent employees from accessing websites deemed inappropriate.
If you can't access the site from work, you can still e-mail your manager asking them to add your registration. You'll still have to sign up to the site first (somewhere other than your workplace), but once that's done you'll be fine. Alternatively, ask your manager to set your up as a floater.
If you're the manager of a squad and you can't access the site from work you'll have to do the management activities from home, or from your mobile phone ... alternatively if you're feeling brave ask your IT department if they're willing to let you use the site.
Until next time,