How to resolve error 403?

I navigated to youtube.com to look up a video. I selected it and the page changed and loaded up to the point where the controls would appear. It froze and reloading in any form would not resolve. In fact, after trying a few times, a white page loaded with this message:

Error 403 Requested target domain not allowed.

Requested target domain not allowed.

Guru Meditation:

XID: 2862294460

Since then, I have been unable to load any youtube page. I continue to get this same screen even if I do a Google search and click on a link to a video in youtube. I have not seen any recent articles for this error in this situation. I am not on a company network, etc.

ThankU,

DarrellSY