We check this website, now realvnc.com is up and dont blocked for our system and other users of the Internet.
So, answer to question: Is realvnc Down Right Now? - NO! realvnc is up!
If you have problem with access to site realvnc, and domain realvnc.com is not avalible.
Clear browser cache and/or try other web browser
(Chrome, Firefox or Safari).